This document provides an updated assessment of the population status of smooth skate in the Funk Island Deep designatable unit in Newfoundland and Labrador waters. Survey indices show declines in both abundance and distribution since the 1980s. A Bayesian surplus production model is used to project population response to different levels of fishing mortality over time to inform conservation strategies under Canada's Species at Risk Act. The population was designated endangered by COSEWIC due to its substantial and prolonged decline.
- Overfishing of rockfish populations off the west coast of the US since the 1960s drastically reduced stocks.
- Rockfish Conservation Areas (RCAs) were established in 2002 with regulations like catch limits, gear restrictions, and seasonal closures to protect habitat and restrict catch.
- Outreach programs educate fishermen on RCA rules and provide devices to return bycatch to reduce mortality. Regulations have proven moderately successful at reducing bycatch and deterring prohibited catches.
This section of the Cohen Commission report on troubles with British Columbia's Faser River sockeye salmon run explores evidence (page 77) that volcanic eruptions have boosted populations by fertilizing large plankton blooms.
The full report, “The Uncertain Future of Fraser River Sockeye,” is available at http://www.cohencommission.ca
This is posted for the Dot Earth blog in relation to controversial efforts by the Haida Gwaii first nation to fertilize runs artificially by distributing iron dust at sea. More soon on Dot Earth: http://j.mp/dotironfert
Scientific American: http://j.mp/sciamironfert
Vancouver Sun:
http://j.mp/vanouvsunironfert
The document summarizes fishing conditions and stocking plans for Pyramid Lake. It reports that catch rates have declined since 2004 but stocking rates have also decreased due to hatchery limitations. Approximately 670,000 fish aged 3-4 inches will be stocked in Pyramid Lake by December from over 800,000 hatched LCT. The Sutcliffe boat launch has opened, and angler data on tagged fish is being collected to inform stocking strategies.
This document summarizes a study that examined fish assemblages in reference and restored tidal freshwater marshes in the San Francisco Estuary. The study compared fish assemblages between one reference marsh and three restored marshes between 1998-1999. Fish were sampled using beach seines and purse seines in different habitats, including open water, submerged aquatic vegetation, offshore areas, tidal sloughs, and marsh edges. Overall, fish assemblages were dominated by introduced species and did not differ significantly between reference and restored marshes. However, fish assemblages did vary between habitats with and without submerged aquatic vegetation, and between offshore and nearshore habitats, with native fishes found more often in tidal sloughs
Berrow et al. 2014. Deployment of Passive Acoustic Monitoring Equipment in th...Ryan Wilson-Parr
This document provides a summary of a cruise conducted in May 2014 that had three main objectives:
1) Deploy passive acoustic monitoring equipment at three sites in the Porcupine Seabight region to monitor cetaceans.
2) Conduct visual surveys for cetaceans and seabirds while transiting to and from the monitoring locations.
3) Collect CTD data at each of the three sites where acoustic monitoring equipment was deployed to record temperature, depth, and salinity.
The cruise aimed to add to the body of knowledge on cetacean and seabird distributions in the Porcupine Seabight, an important habitat.
This study analyzed historical tag and recapture data from over 8,600 barred sand bass tagged in southern California between the 1960s and 1990s to understand their spawning-related movements. The data suggest barred sand bass reside at spawning grounds like Huntington Beach Flats for approximately one month during peak spawning season. While most non-spawning season recaptures occurred within 1 km of spawning locations, migrant fish averaged 13 km in movement away from spawning sites after spawning. The study also found evidence of site fidelity, as barred sand bass tended to return to the same spawning locations in subsequent years.
This document summarizes Southern California Edison's marine mitigation program for the San Onofre Nuclear Generating Station. It describes the station's once-through cooling system and its impacts on marine life, including entrainment of fish eggs and larvae and effects on the nearby kelp forest. As required by the Coastal Commission, SCE established a mitigation program that included constructing 150 acres of artificial reef habitat and 150 acres of tidal wetlands to compensate for these impacts. The program also included studies of the station's fish return system and long-term monitoring. SCE has spent over $172 million on the mitigation program to date with additional ongoing monitoring costs.
This research article describes efforts to balance fisheries management goals of conserving overfished species while allowing fishing of abundant stocks. Large-scale fishery closures implemented in the late 1990s successfully reduced overfishing on the U.S. West Coast, but also constrained fishing and reduced data collection. The study developed and tested video survey and experimental fishing techniques to determine if abundant groundfish species could be caught in rocky habitats with minimal bycatch of rebuilding species still under restrictions. Comparing video surveys to fishing catches indicated modified fishing gear could target abundant stocks while limiting impacts on protected species, improving data collection as populations recover.
- Overfishing of rockfish populations off the west coast of the US since the 1960s drastically reduced stocks.
- Rockfish Conservation Areas (RCAs) were established in 2002 with regulations like catch limits, gear restrictions, and seasonal closures to protect habitat and restrict catch.
- Outreach programs educate fishermen on RCA rules and provide devices to return bycatch to reduce mortality. Regulations have proven moderately successful at reducing bycatch and deterring prohibited catches.
This section of the Cohen Commission report on troubles with British Columbia's Faser River sockeye salmon run explores evidence (page 77) that volcanic eruptions have boosted populations by fertilizing large plankton blooms.
The full report, “The Uncertain Future of Fraser River Sockeye,” is available at http://www.cohencommission.ca
This is posted for the Dot Earth blog in relation to controversial efforts by the Haida Gwaii first nation to fertilize runs artificially by distributing iron dust at sea. More soon on Dot Earth: http://j.mp/dotironfert
Scientific American: http://j.mp/sciamironfert
Vancouver Sun:
http://j.mp/vanouvsunironfert
The document summarizes fishing conditions and stocking plans for Pyramid Lake. It reports that catch rates have declined since 2004 but stocking rates have also decreased due to hatchery limitations. Approximately 670,000 fish aged 3-4 inches will be stocked in Pyramid Lake by December from over 800,000 hatched LCT. The Sutcliffe boat launch has opened, and angler data on tagged fish is being collected to inform stocking strategies.
This document summarizes a study that examined fish assemblages in reference and restored tidal freshwater marshes in the San Francisco Estuary. The study compared fish assemblages between one reference marsh and three restored marshes between 1998-1999. Fish were sampled using beach seines and purse seines in different habitats, including open water, submerged aquatic vegetation, offshore areas, tidal sloughs, and marsh edges. Overall, fish assemblages were dominated by introduced species and did not differ significantly between reference and restored marshes. However, fish assemblages did vary between habitats with and without submerged aquatic vegetation, and between offshore and nearshore habitats, with native fishes found more often in tidal sloughs
Berrow et al. 2014. Deployment of Passive Acoustic Monitoring Equipment in th...Ryan Wilson-Parr
This document provides a summary of a cruise conducted in May 2014 that had three main objectives:
1) Deploy passive acoustic monitoring equipment at three sites in the Porcupine Seabight region to monitor cetaceans.
2) Conduct visual surveys for cetaceans and seabirds while transiting to and from the monitoring locations.
3) Collect CTD data at each of the three sites where acoustic monitoring equipment was deployed to record temperature, depth, and salinity.
The cruise aimed to add to the body of knowledge on cetacean and seabird distributions in the Porcupine Seabight, an important habitat.
This study analyzed historical tag and recapture data from over 8,600 barred sand bass tagged in southern California between the 1960s and 1990s to understand their spawning-related movements. The data suggest barred sand bass reside at spawning grounds like Huntington Beach Flats for approximately one month during peak spawning season. While most non-spawning season recaptures occurred within 1 km of spawning locations, migrant fish averaged 13 km in movement away from spawning sites after spawning. The study also found evidence of site fidelity, as barred sand bass tended to return to the same spawning locations in subsequent years.
This document summarizes Southern California Edison's marine mitigation program for the San Onofre Nuclear Generating Station. It describes the station's once-through cooling system and its impacts on marine life, including entrainment of fish eggs and larvae and effects on the nearby kelp forest. As required by the Coastal Commission, SCE established a mitigation program that included constructing 150 acres of artificial reef habitat and 150 acres of tidal wetlands to compensate for these impacts. The program also included studies of the station's fish return system and long-term monitoring. SCE has spent over $172 million on the mitigation program to date with additional ongoing monitoring costs.
This research article describes efforts to balance fisheries management goals of conserving overfished species while allowing fishing of abundant stocks. Large-scale fishery closures implemented in the late 1990s successfully reduced overfishing on the U.S. West Coast, but also constrained fishing and reduced data collection. The study developed and tested video survey and experimental fishing techniques to determine if abundant groundfish species could be caught in rocky habitats with minimal bycatch of rebuilding species still under restrictions. Comparing video surveys to fishing catches indicated modified fishing gear could target abundant stocks while limiting impacts on protected species, improving data collection as populations recover.
This study analyzed the stomach contents and stable isotope ratios of over 960 juvenile fish and their potential food sources from pelagic and littoral habitats in the tidal freshwater region of the San Francisco Estuary. The results showed evidence of two predominant food web pathways. Pelagic fish and some littoral fish relied on a zooplankton-phytoplankton trophic pathway, while the majority of littoral fish had diets and carbon isotope ratios consistent with energy from submerged aquatic vegetation and epiphytic macroalgae. Analysis with a mixing model revealed that littoral fish obtained the overall majority of their nutrition from consuming grazer amphipods. Examining both stable isot
Fish scavenging behaviour in recently trawled areasratupura
This study examined the diets of four fish species to determine if they feed on animals damaged by beam trawling. The researchers conducted beam trawling experiments off the coast of Wales and analyzed the stomach contents of fish caught before and after trawling. They found that two species, gurnards and whiting, significantly increased their food intake after an area was trawled, eating more of certain prey like amphipods that were likely disturbed by the trawling. Observations with sonar also detected more fish concentrated near the trawl tracks compared to untrawled areas. The results suggest these fish rapidly migrate into recently trawled areas to scavenge on damaged or disturbed animals, potentially altering community structure with
The document provides information on the history, economic value, stock status, environmental impacts, stakeholders, and current management of the American lobster fishery. It discusses how lobsters were once used as fertilizer but became a culinary prize, the development of trap fishing, and the history of management from the 1940s onward. Stock status varies by region, with Gulf of Maine and Georges Bank stocks increasing but Southern New England critically depleted. The fishery generates hundreds of millions annually for New England. Current management divides the fishery into areas and stocks and regulates effort and catch through limits. Recommendations focus on improving conditions for the Southern New England stock and considering ecosystem and spatial issues.
Paeter Garcia - Best Best Kreiger C A Contract Cities Association Prese...Contract Cities
This document summarizes litigation related to California's Delta and water projects. It discusses the State Water Project which provides water to 25 million Californians. Fisheries in the Delta have declined due to various stressors. The State and Federal water projects have faced increased regulation to protect fisheries. After 2006, court rulings imposed additional operational limits beyond existing regulations to protect Delta smelt. New biological opinions in 2008-2009 proposed further restrictions, reducing State Water Project deliveries by around 1 million acre-feet per year. Multiple lawsuits have been filed challenging these new biological opinions.
Jan 2009 Geog Investigation Mark SchemeHarpal Bains
The student's investigation into deprivation and environmental quality in a city has some limitations:
1. The data collection techniques of questionnaires and surveys are subjective and open to bias.
2. Presenting the data as maps and diagrams does not show correlations or causation between variables.
3. No information is provided about sampling strategies, so the reliability of the results is unclear.
US Fleet Forces Environmental ReadinessBryanHall58
The document discusses the United States Fleet Forces' environmental readiness programs, which include monitoring marine species and their responses to Navy training activities, conducting research on topics like marine mammal tagging, and ensuring compliance with environmental laws for actions like home basing and expanding aircraft operations. Key programs mentioned are the Integrated Comprehensive Monitoring Program, the Behavioral Response Study on beaked whales and pilot whales, and pinniped tagging in the Chesapeake Bay area.
2011 Perspective on DoD’s Efforts Relating to Legacy Underwater Military Munit…Geoffrey Carton
Presentation from 3rd International Dialogue on Underwater Munitions, Sopot, Poland. Provides an overview of US efforts (such as site inventory, safety outreach and research) concerning munitions in the underwater environment.
This document provides an overview of Commander Navy Region Northwest's natural resource management programs across 4 installations and 16 reporting units. It summarizes that they manage over 66,000 acres of ecosystem, including federally-listed and species of concern. Key programs include habitat management, forestry, fire control, hunting/fishing, and invasive species control. Recent accomplishments include aquatic habitat restoration, estuary mitigation, and surveys of species like marbled murrelets. Lessons learned include changes to acoustic thresholds in consultations and linking natural resource projects more closely to installation missions.
This document provides information about NAVFAC Pacific's natural resources program and staff. It includes:
- A list of NAVFAC Pacific's areas of responsibility and bases within different regions.
- Contact information for the leadership of NAVFAC Pacific's Environmental Planning and Conservation division.
- Rosters of the Terrestrial Natural Resources and Applied Biology staff, and Marine Resources staff, with names, emails, and phone numbers.
- Brief descriptions of the types of projects and activities the Terrestrial Natural Resources group undertakes, such as ESA consultations and implementing Integrated Natural Resources Management Plans.
- Examples of successes in translocating endangered tree snails during the Marine Corps
The document summarizes operations and research activities at KMRS in October. First, it describes the pearl seeding process where mature oysters are brought into the hatchery and seeded with nuclei by technicians. Seeded oysters are then mounted on panels and returned to sea lines. The document also introduces the latest interns, Hayley and Maddi, and describes their experiences. Finally, it provides details on two research collaborations in October studying juvenile fish recruitment and coral communities, and another in November examining soft sediment habitats, seagrass productivity, and grazing.
This document summarizes natural and cultural resource management activities at a naval facility. It outlines that the facility supports various military missions through managing over 87,000 acres of land, which includes 17,000 acres of wetlands and waterways. Key programs at the facility include threatened and endangered species surveys, forestry management, and invasive species control. Recent accomplishments include establishing a regional bat database, GPS tracking of Atlantic sturgeon, and completing all fiscal year 2019 funds execution. Natural resource management supports the military mission through compliance activities and programs that balance training needs with environmental protection.
Spawning Behavior of Trout and Utility of Redd Countsrobertvierck
Presented by Dr. Robert F. Carline at the November 2016 Meeting of the Spring Creek Chapter of Trout Unlimited, this presentation details the spawning behavior of trout in streams. It also addressed the value of utilizing Redd Counts to determine the health of stream.
WGC 2016 poster on RCA EFP fishing surveysSteve Rienecke
This study aimed to develop methods for commercial fishermen to target healthy rockfish stocks while minimizing catches of rebuilding species. Researchers used existing data and local knowledge to identify areas and tested fishing gear that achieved catch ratios of over 10 pounds of target species for every 1 pound of rebuilding species. Visual surveys confirmed the presence of rebuilding species where none were caught, indicating the gear was selectively catching target species. The methods showed potential for fishermen to profitably target rebuilt populations while protecting depleted species.
This document summarizes CSA's services related to ports, harbors, and beaches. CSA has over 45 years of experience providing environmental services to support marine construction and dredging projects, including port development, dredging, oil and gas terminals, shipping, and beach nourishment. Their services include environmental permitting, surveys of marine habitats, mitigation of impacts to corals and seagrasses, monitoring programs, and working with resource agencies. The document highlights two representative projects involving monitoring of hardbottom habitats near a beach nourishment project in Florida and relocating corals and transplanting seagrasses as mitigation for a dredging project in Miami Harbor.
The document summarizes a shellfish study conducted at Penny Lane Marina in Margate, NJ to assess the impact of a proposed floating dock system and fixed access dock. No juvenile hard clams were found across 9 square feet sampled. Three adult hard clams were found across 480 square feet sampled, equating to a density of 0.0062 clams per square foot, below the threshold for designation as shellfish habitat. Water quality parameters including temperature, salinity, dissolved oxygen, and pH were within suitable ranges for hard clams, indicating they could potentially live in the area but are not currently present at viable densities.
Growth patterns, sex ratios and fecundity estimates in blue crab (callinectes...Alexander Decker
- The study investigated growth patterns, sex ratios, and fecundity estimates in blue crab (Callinectes amnicola) from Yewa River in southwest Nigeria between June 2011 and May 2012.
- A total of 250 crabs were collected ranging from 5.2-14.8 cm in length and 8.2-165 g in weight. Growth was negative allometric for both sexes. The sex ratio was 1 male to 1.45 females.
- Fecundity estimates ranged from 260,000 to 2,150,692 eggs. Relationships between fecundity and carapace length and weight were determined. The study provides baseline data on the population dynamics of blue crab
This document provides an overview and synthesis of the status and trends of Caribbean coral reefs from 1970 to 2012. It analyzes data on the biological abundance of corals, macroalgae, parrotfish and Diadema antillarum from over 40 reef sites across the Caribbean. The data shows long-term declines in coral cover and increases in macroalgal cover over this period. It also examines the main anthropogenic drivers of reef degradation, including overfishing, coastal pollution, climate change and the impacts of hurricanes. Finally, it provides recommendations to help guide management efforts to conserve these valuable ecosystems.
A shellfish study was conducted over two days in December 2011 to determine if the environmental conditions at Fish Finder Marine in Brigantine, NJ support shellfish populations in relation to a proposed marina expansion. A total of 24 sites were sampled using GPS and grab samples. One juvenile hard clam and 19 adult hard clams were found, indicating some viable habitat areas but densities below the threshold for designation as shellfish habitat. Water quality parameters were also measured and fell within normal ranges for the area. The study concluded that the shellfish densities did not substantiate the area as viable hard clam habitat for the proposed expansion.
This cruise summary report describes a research cruise conducted from May 17-24, 2015 that aimed to study the chronic effects of bottom trawling on benthic communities and fish in the Celtic Sea. A team of scientists from Spain and the UK sampled 12 stations in a Nephrops fishing ground using grabs to collect infauna, imaging to assess bioturbation, and trawls to collect fish and invertebrates. Bad weather limited sampling to 5 days, but replicate samples were collected at each station. Infauna and fish length and weight data were recorded to analyze impacts on community composition and trophic structure across a trawling gradient. Tissue samples were also taken for stable isotope analysis to further assess
This document summarizes trends in the American lobster fishery in Newfoundland and discusses recent management changes. It provides data on lobster landings by fishing area from 1992-2005, which show overall landings declining from 3200 tonnes to 1800 tonnes from 1992-2000 before increasing again to 2600 tonnes in 2005. It also presents catch and effort data from long-term monitoring sites in three lobster fishing areas, which indicate high exploitation rates and catches composed primarily of incoming recruits each year. Due to insufficient data, the overall status of the lobster resource cannot be assessed at this time.
The document analyzes audience research from a survey about magazine preferences. It summarizes key findings such as:
- Most respondents were female, between ages 18-24.
- Design was the main reason people buy items.
- Respondents wanted to read about band interviews and touring bands.
- Both print and digital magazines should be offered to maximize revenue.
- Colors, prices, and additional items need to be considered to attract and retain readers.
This study analyzed the stomach contents and stable isotope ratios of over 960 juvenile fish and their potential food sources from pelagic and littoral habitats in the tidal freshwater region of the San Francisco Estuary. The results showed evidence of two predominant food web pathways. Pelagic fish and some littoral fish relied on a zooplankton-phytoplankton trophic pathway, while the majority of littoral fish had diets and carbon isotope ratios consistent with energy from submerged aquatic vegetation and epiphytic macroalgae. Analysis with a mixing model revealed that littoral fish obtained the overall majority of their nutrition from consuming grazer amphipods. Examining both stable isot
Fish scavenging behaviour in recently trawled areasratupura
This study examined the diets of four fish species to determine if they feed on animals damaged by beam trawling. The researchers conducted beam trawling experiments off the coast of Wales and analyzed the stomach contents of fish caught before and after trawling. They found that two species, gurnards and whiting, significantly increased their food intake after an area was trawled, eating more of certain prey like amphipods that were likely disturbed by the trawling. Observations with sonar also detected more fish concentrated near the trawl tracks compared to untrawled areas. The results suggest these fish rapidly migrate into recently trawled areas to scavenge on damaged or disturbed animals, potentially altering community structure with
The document provides information on the history, economic value, stock status, environmental impacts, stakeholders, and current management of the American lobster fishery. It discusses how lobsters were once used as fertilizer but became a culinary prize, the development of trap fishing, and the history of management from the 1940s onward. Stock status varies by region, with Gulf of Maine and Georges Bank stocks increasing but Southern New England critically depleted. The fishery generates hundreds of millions annually for New England. Current management divides the fishery into areas and stocks and regulates effort and catch through limits. Recommendations focus on improving conditions for the Southern New England stock and considering ecosystem and spatial issues.
Paeter Garcia - Best Best Kreiger C A Contract Cities Association Prese...Contract Cities
This document summarizes litigation related to California's Delta and water projects. It discusses the State Water Project which provides water to 25 million Californians. Fisheries in the Delta have declined due to various stressors. The State and Federal water projects have faced increased regulation to protect fisheries. After 2006, court rulings imposed additional operational limits beyond existing regulations to protect Delta smelt. New biological opinions in 2008-2009 proposed further restrictions, reducing State Water Project deliveries by around 1 million acre-feet per year. Multiple lawsuits have been filed challenging these new biological opinions.
Jan 2009 Geog Investigation Mark SchemeHarpal Bains
The student's investigation into deprivation and environmental quality in a city has some limitations:
1. The data collection techniques of questionnaires and surveys are subjective and open to bias.
2. Presenting the data as maps and diagrams does not show correlations or causation between variables.
3. No information is provided about sampling strategies, so the reliability of the results is unclear.
US Fleet Forces Environmental ReadinessBryanHall58
The document discusses the United States Fleet Forces' environmental readiness programs, which include monitoring marine species and their responses to Navy training activities, conducting research on topics like marine mammal tagging, and ensuring compliance with environmental laws for actions like home basing and expanding aircraft operations. Key programs mentioned are the Integrated Comprehensive Monitoring Program, the Behavioral Response Study on beaked whales and pilot whales, and pinniped tagging in the Chesapeake Bay area.
2011 Perspective on DoD’s Efforts Relating to Legacy Underwater Military Munit…Geoffrey Carton
Presentation from 3rd International Dialogue on Underwater Munitions, Sopot, Poland. Provides an overview of US efforts (such as site inventory, safety outreach and research) concerning munitions in the underwater environment.
This document provides an overview of Commander Navy Region Northwest's natural resource management programs across 4 installations and 16 reporting units. It summarizes that they manage over 66,000 acres of ecosystem, including federally-listed and species of concern. Key programs include habitat management, forestry, fire control, hunting/fishing, and invasive species control. Recent accomplishments include aquatic habitat restoration, estuary mitigation, and surveys of species like marbled murrelets. Lessons learned include changes to acoustic thresholds in consultations and linking natural resource projects more closely to installation missions.
This document provides information about NAVFAC Pacific's natural resources program and staff. It includes:
- A list of NAVFAC Pacific's areas of responsibility and bases within different regions.
- Contact information for the leadership of NAVFAC Pacific's Environmental Planning and Conservation division.
- Rosters of the Terrestrial Natural Resources and Applied Biology staff, and Marine Resources staff, with names, emails, and phone numbers.
- Brief descriptions of the types of projects and activities the Terrestrial Natural Resources group undertakes, such as ESA consultations and implementing Integrated Natural Resources Management Plans.
- Examples of successes in translocating endangered tree snails during the Marine Corps
The document summarizes operations and research activities at KMRS in October. First, it describes the pearl seeding process where mature oysters are brought into the hatchery and seeded with nuclei by technicians. Seeded oysters are then mounted on panels and returned to sea lines. The document also introduces the latest interns, Hayley and Maddi, and describes their experiences. Finally, it provides details on two research collaborations in October studying juvenile fish recruitment and coral communities, and another in November examining soft sediment habitats, seagrass productivity, and grazing.
This document summarizes natural and cultural resource management activities at a naval facility. It outlines that the facility supports various military missions through managing over 87,000 acres of land, which includes 17,000 acres of wetlands and waterways. Key programs at the facility include threatened and endangered species surveys, forestry management, and invasive species control. Recent accomplishments include establishing a regional bat database, GPS tracking of Atlantic sturgeon, and completing all fiscal year 2019 funds execution. Natural resource management supports the military mission through compliance activities and programs that balance training needs with environmental protection.
Spawning Behavior of Trout and Utility of Redd Countsrobertvierck
Presented by Dr. Robert F. Carline at the November 2016 Meeting of the Spring Creek Chapter of Trout Unlimited, this presentation details the spawning behavior of trout in streams. It also addressed the value of utilizing Redd Counts to determine the health of stream.
WGC 2016 poster on RCA EFP fishing surveysSteve Rienecke
This study aimed to develop methods for commercial fishermen to target healthy rockfish stocks while minimizing catches of rebuilding species. Researchers used existing data and local knowledge to identify areas and tested fishing gear that achieved catch ratios of over 10 pounds of target species for every 1 pound of rebuilding species. Visual surveys confirmed the presence of rebuilding species where none were caught, indicating the gear was selectively catching target species. The methods showed potential for fishermen to profitably target rebuilt populations while protecting depleted species.
This document summarizes CSA's services related to ports, harbors, and beaches. CSA has over 45 years of experience providing environmental services to support marine construction and dredging projects, including port development, dredging, oil and gas terminals, shipping, and beach nourishment. Their services include environmental permitting, surveys of marine habitats, mitigation of impacts to corals and seagrasses, monitoring programs, and working with resource agencies. The document highlights two representative projects involving monitoring of hardbottom habitats near a beach nourishment project in Florida and relocating corals and transplanting seagrasses as mitigation for a dredging project in Miami Harbor.
The document summarizes a shellfish study conducted at Penny Lane Marina in Margate, NJ to assess the impact of a proposed floating dock system and fixed access dock. No juvenile hard clams were found across 9 square feet sampled. Three adult hard clams were found across 480 square feet sampled, equating to a density of 0.0062 clams per square foot, below the threshold for designation as shellfish habitat. Water quality parameters including temperature, salinity, dissolved oxygen, and pH were within suitable ranges for hard clams, indicating they could potentially live in the area but are not currently present at viable densities.
Growth patterns, sex ratios and fecundity estimates in blue crab (callinectes...Alexander Decker
- The study investigated growth patterns, sex ratios, and fecundity estimates in blue crab (Callinectes amnicola) from Yewa River in southwest Nigeria between June 2011 and May 2012.
- A total of 250 crabs were collected ranging from 5.2-14.8 cm in length and 8.2-165 g in weight. Growth was negative allometric for both sexes. The sex ratio was 1 male to 1.45 females.
- Fecundity estimates ranged from 260,000 to 2,150,692 eggs. Relationships between fecundity and carapace length and weight were determined. The study provides baseline data on the population dynamics of blue crab
This document provides an overview and synthesis of the status and trends of Caribbean coral reefs from 1970 to 2012. It analyzes data on the biological abundance of corals, macroalgae, parrotfish and Diadema antillarum from over 40 reef sites across the Caribbean. The data shows long-term declines in coral cover and increases in macroalgal cover over this period. It also examines the main anthropogenic drivers of reef degradation, including overfishing, coastal pollution, climate change and the impacts of hurricanes. Finally, it provides recommendations to help guide management efforts to conserve these valuable ecosystems.
A shellfish study was conducted over two days in December 2011 to determine if the environmental conditions at Fish Finder Marine in Brigantine, NJ support shellfish populations in relation to a proposed marina expansion. A total of 24 sites were sampled using GPS and grab samples. One juvenile hard clam and 19 adult hard clams were found, indicating some viable habitat areas but densities below the threshold for designation as shellfish habitat. Water quality parameters were also measured and fell within normal ranges for the area. The study concluded that the shellfish densities did not substantiate the area as viable hard clam habitat for the proposed expansion.
This cruise summary report describes a research cruise conducted from May 17-24, 2015 that aimed to study the chronic effects of bottom trawling on benthic communities and fish in the Celtic Sea. A team of scientists from Spain and the UK sampled 12 stations in a Nephrops fishing ground using grabs to collect infauna, imaging to assess bioturbation, and trawls to collect fish and invertebrates. Bad weather limited sampling to 5 days, but replicate samples were collected at each station. Infauna and fish length and weight data were recorded to analyze impacts on community composition and trophic structure across a trawling gradient. Tissue samples were also taken for stable isotope analysis to further assess
This document summarizes trends in the American lobster fishery in Newfoundland and discusses recent management changes. It provides data on lobster landings by fishing area from 1992-2005, which show overall landings declining from 3200 tonnes to 1800 tonnes from 1992-2000 before increasing again to 2600 tonnes in 2005. It also presents catch and effort data from long-term monitoring sites in three lobster fishing areas, which indicate high exploitation rates and catches composed primarily of incoming recruits each year. Due to insufficient data, the overall status of the lobster resource cannot be assessed at this time.
The document analyzes audience research from a survey about magazine preferences. It summarizes key findings such as:
- Most respondents were female, between ages 18-24.
- Design was the main reason people buy items.
- Respondents wanted to read about band interviews and touring bands.
- Both print and digital magazines should be offered to maximize revenue.
- Colors, prices, and additional items need to be considered to attract and retain readers.
Poke-trainers across the world are suffering injuries due to being fixated on their screens. Check these saftey measure tips issued by Japanese Government, to play the game safely.
Time Inc is an American publishing company founded in 1922 by Henry Luce and Britton Hadden. It publishes over 90 magazines worldwide, including the influential weekly magazine Time. While Time Inc has experienced success with international subsidiaries and magazine acquisitions, its recent financial reports show losses, suggesting a gap in its market coverage that a new magazine could help fill.
Santhosh Kumar is seeking a growth-oriented position in human resources, industrial relations, or personnel administration. He has over 3 years of experience in HR roles across various manufacturing companies. His experience includes managing payroll, employee databases, training, statutory compliance, performance reviews, and industrial relations. He is proficient in SAP modules and has experience handling union activities.
This document discusses questions chosen for a Survey Monkey survey to help identify the target audience for a new magazine. The questions were selected because they are relevant to the magazine and will help determine the demographic audience. Repeating the same questions will provide data on the intended readership.
The government rejected Google Street View in India due to security concerns. Authorities fear that panoramic street views could aid terrorists by revealing details of potential targets. They cite past instances where terrorists used online maps and photos to plan attacks. The government is proposing new regulations to restrict geospatial data access and penalize inaccurate maps of India that could undermine national security.
Mobile apps are no longer limited to single platforms, and by the end of 2016 there will be over 10 billion internet-connected devices. Future trends in mobile app development include cross-platform apps that work across Android and iOS, the rise of apps for the Internet of Things, and increased use of developer tools and cloud computing. Other growing areas are enterprise apps, location-based services, and mobile security apps as people's lives increasingly involve mobile devices.
The document summarizes the key features of the iPhone SE. It has the same advanced A9 chip as the iPhone 6s, allowing it to be the most powerful 4-inch phone ever made by Apple. It has a 12-megapixel camera that can capture high-quality photos and 4K videos. The iPhone SE also features Touch ID, Apple Pay, a Retina display, Live Photos, iCloud Photo Library, Bluetooth, and the voice assistant Siri. Overall, the document outlines that the iPhone SE packs high-end smartphone technology into a compact 4-inch form factor.
The summary provides an overview of the Sea Duck Joint Venture newsletter. It discusses:
1) The newsletter shares news about the SDJV program and its work supporting research, surveys, and citizen science on sea duck populations.
2) The SDJV was created in 1999 to study declining sea duck populations and promote research and monitoring. It focuses on 5 species of highest concern.
3) The newsletter includes stories from partners on recent work counting eider duck migrations in Alaska and capturing and tagging sea ducks in Cape Cod Bay.
Adélie Penguin Population Trends in Cape BirdJessica Carde
1) The document analyzes historic aerial photographs from 1956-2009 of the Cape Bird Adélie penguin colony in Antarctica to study population trends over time in response to climate change.
2) Using GIS software, the author counts penguins in 1983 photos and outlines guano-stained areas in older photos to estimate colony sizes. All three rookeries at Cape Bird increased in size between 1956-2009, with the largest growth in the Middle Rookery.
3) Climate change, competitive release from declining whale populations, and decreased fishing of prey species likely all contributed to the increasing Cape Bird penguin population observed over the past 60 years.
This document summarizes research on coastal cutthroat trout populations in South Puget Sound, Washington. It finds that coastal cutthroat trout in the region:
1) Support important sport fisheries but have declined due to overharvesting historically.
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1. Canadian Science Advisory Secretariat (CSAS)
Research Document 2013/098
Newfoundland and Labrador Region
November 2013
Assessment of the Potential for Recovery of Smooth Skate (Malacoraja senta
Garman 1885) in the Funk Island Deep Designatable Unit
M.R. Simpson, C.M. Miri, L.G.S. Mello, R.K. Collins, and J.A. Bailey
Science Branch
Fisheries and Oceans Canada
PO Box 5667
St. John’s NL A1C 5X1
3. iii
ABSTRACT
Decline in abundance and reduction in the extent of distribution have been observed in several
Smooth Skate (Malacoraja senta Garman 1885) populations inhabiting Canadian waters,
despite the absence of directed commercial fisheries for this species. The main concentration
was centered in NAFO Div. 2J3K, in Funk Island Deep designatable unit (DU), until the 1980s,
when it experienced a substantial and protracted decline in area of occupancy, as well as
abundance of both juveniles and adults. Consequently, the Committee on the Status of
Endangered Wildlife in Canada (COSEWIC) has recommended that the Funk Island Deep
population be designated as Endangered, As a result, Fisheries and Oceans Canada (DFO) has
initiated a Recovery Potential Assessment (RPA) of the Funk Island Deep DU under Canada’s
Species at Risk Act (SARA), to be used in formulating and evaluating conservation and
management strategies for this species in terms of risk of extinction. This document provides
updates in survey indices and commercial removals of Smooth Skate in the Funk Island Deep
DU, and employs a Bayesian surplus production model to project population response to
differing levels of fishing mortality (F) over varying time periods.
4. iv
Évaluation du potentiel de rétablissement de la raie à queue de velours (Malacoraja senta
Garman 1885) dans l'unité désignable de la fosse de l'île Funk
RESUME
L’abondance et l’étendue de la répartition de plusieurs populations de raie à queue de velours
(Malacoraja senta Garman 1885) des eaux canadiennes ont diminué, bien que cette espèce ne
soit pas menacée par la pêche commerciale. La concentration principale se trouvait dans la
division 2J3K (unité désignable de la fosse de l’île Funk) de l'Organisation des pêches de
l'Atlantique Nord-Ouest jusqu’aux années 1980, soit lorsqu'elle a enregistré un déclin prononcé
et prolongé quant aux facteurs d'aire d'occurrence et d'abondance des jeunes et des adultes.
Par conséquent, le Comité sur la situation des espèces en péril au Canada (COSEPAC) a
recommandé que la population de la fosse de l'île Funk soit désignée comme espèce en voie
de disparition. Ainsi, Pêches et Océans Canada a réalisé une évaluation du potentiel de
rétablissement de l'unité désignable de la fosse de l'île Funk, en vertu de la Loi sur les espèces
en péril du Canada, afin d'élaborer et d'évaluer les stratégies de conservation et de gestion
liées à l'espèce en question pour ce qui est du risque d'extinction. Le présent document révèle
les mises à jour en matière d'indices d'abondance et de prélèvements par la pêche
commerciale de la raie à queue de velours dans l'unité désignable de la fosse de l'île Funk et se
sert d'un modèle bayésien de production excédentaire pour prévoir la réaction de la population
envers les différents niveaux de mortalité par pêche au cours de diverses périodes.
5. 1
INTRODUCTION
Declines in abundance and reduction in extent of distribution of Smooth Skate (Malacoraja
senta Garman 1885, Family Rajidae) in the Northwest Atlantic Ocean have recently been
reported in Canadian waters; including populations from the southern Gulf of St. Lawrence,
Scotian Shelf, and in Newfoundland and Labrador (NL) waters (Simon et al. 2011, 2012;
Simpson et al. 2011a). These declines have been observed despite an absence of directed
commercial fisheries for this species, with removals limited to bycatch in fisheries targeting other
species (Kulka 1986; Kulka et al. 2006; NOAA/NMFS 2000, 2009; Simpson et al. 2011a).
Vulnerability to exploitation, even when incidentally captured at low levels, has been
documented for various elasmobranch species by Frisk et al. (2001); although not for Smooth
Skate. Low reproductive potential resulting from slow growth, late sexual maturation, low
fecundity, and long reproductive cycles is thought to lead to low resilience to fishing mortality
(Hoenig and Gruber 1990; Smith et al. 1998; Musick et al. 2000; Musick 2004).
Recently, COSEWIC has assessed the status of Smooth Skate in Canadian waters (COSEWIC
2012). The Committee on the Status of Endangered Wildlife in Canada recommended that the
Funk Island Deep DU of Smooth Skate be listed as Endangered, while the Laurentian-Scotian
DU is considered to be of Special Concern. Two additional DUs, located in the Hopedale
Channel and the Nose of the Grand Bank, were considered to be data deficient.
This paper updates the information provided for the COSEWIC assessment of Smooth Skate in
the Funk Island Deep DU, to facilitate a RPA of this population, as required under Canada’s
SARA. It provides recent trends in abundance and distribution, as well as updated estimates of
bycatch mortality from commercial fishery monitoring data. In addition, the paper provides
stochastic projections of population biomass, using a Bayesian surplus production model, to
facilitate the formulation of appropriate conservation and management actions to mitigate
extinction risk.
ASSESSMENT
DISTRIBUTION, ABUNDANCE AND HABITAT ASSOCIATIONS
Surveys - NL Region
Bottom trawl research surveys have been conducted by DFO over the continental shelves of
Newfoundland and Labrador in the fall (1977-2012, NAFO Div. 2J3K; NAFO Div. 3L was added
in 1981) in the Funk Island Deep DU area. Surveys were originally designed to provide
estimates of abundance for commercially important groundfish species, such as Atlantic Cod
(Gadus morhua) and redfish (Sebastes sp.). However, Smooth Skate distributes in similar depth
and latitudinal ranges, so the survey footprint adequately covers the distribution range of this
species in this area.
Research surveys in the NL Region employ a random stratified design, with fishing tow
allocation based on depth intervals and location (latitude and longitude). A summary of the
survey design employed in NL waters since 1970 can be found in Doubleday (1981).
Fall surveys in Div. 2J3K were conducted by RV Gadus Atlantica until 1994. In 1995-2000, they
were conducted mainly by RV Teleost; although RV Wilfred Templeman surveyed part of
Div. 3K. Div. 3L surveys were conducted by RV A.T. Cameron (1971-82), and RV Wilfred
Templeman or its sister ship RV Alfred Needler. An Engel 145 Hi-lift trawl was used for fall
surveys from 1977 to 1994, and a Campelen 1800 shrimp trawl from 1995 to present. While
6. 2
survey design has remained constant, additional strata have been included in recent years;
along with modifications to some of the original strata (Bishop 1994). One significant change in
the surveys was the addition of shallower (< 50 m) and deeper strata (> 700 m) after 1993;
although tows at depths < 50 m were occasionally recorded in earlier years. Additional causes
of variation in survey coverage are discussed in detail by Brodie and Stansbury (2007), and
Healey and Brodie (2009). It should be noted that no Smooth Skate conversion factors exist for
the Engel to Campelen gear change; therefore, each time series must be considered
independently.
Spatial Distribution and Habitat Associations
Geo-referenced catch and hydrographic data for the fall bottom trawl survey were used to
assess the spatial distribution of Smooth Skate in the Funk Island Deep DU. Maps of the
geographic distribution of catch rate (number/tow) were plotted using data from this survey, for
each year from 2009-12.
Area of Occupancy
The area of occupancy (At) was calculated in each year t as follows:
where Yijkl is the number of fish in length interval l caught in tow i at site j in stratum k, ak is the
area of the stratum k (km2
), Nk is the number of sites sampled in stratum k, nj is the number of
tows conducted at site j, and S is the number of strata.
Abundance Indices and Size Composition
Survey indices for the Funk Island Deep DU were expressed as mean fish number per standard
tow, weight per standard tow, relative abundance and relative biomass. Since the fall survey
footprint does not conform to Smooth Skate DU boundaries, survey areas were segmented to
conform to DU locations: Div. 2J3K and a small portion of Div. 3L represents the Funk Island
Deep DU. McPhie and Campana (2009a, 2009b) indicated that Smooth Skate < 48 cm and
≥ 48 cm Total Length (TL) roughly corresponded to the immature and mature components of the
population, respectively. Therefore, where possible, estimation was also done separately for
immature (< 48 cm) and mature (≥ 48 cm) skates, and indices were expressed as number per
tow, and relative abundance.
SURPLUS PRODUCTION MODELLING
A Bayesian surplus production model was implemented in Winbugs with an R interface for this
DU. See models for Roundnose Grenadier (Simpson et al. 2011b) and American Plaice (Bailey
2011; Morgan et al. 2011) for more details.
Biomass was modeled historically using estimated priors for K, r, and q (Table 1). Catch and
stock biomass estimates from Canadian RV surveys were incorporated into the model as
observed data with error.
WinBUGS (v.1.4.3), was used for all Bayesian Markov Chain Monte Carlo with Gibbs sampling
models. WinBUGS was called from R (v.2.13.1) using the R2WinBUGS package. Convergence
and model diagnostics were all run from R using the Bayesian Output Analysis (BOA) library.
Models were run using 100000 iterations and a burn-in period of 40000 with thinning at 20 to
reduce the possibility of autocorrelation within the series.
>
== ∑∑∑ === otherwise0
0if1
where
111
ijkl
n
i jk
k
N
j
S
k
t
Y
II
nN
a
A
jk
7. 3
Data
The data from the Funk Island DU spanned 1981-2010, and included a gear change (Engel to
Campelen). These data were not converted, and were used as separate series in the model, as
indicated below:
• Canadian Autumn RV Survey Indices: Engel Series – 1981-94
• Canadian Autumn RV Survey Indices: Campelen Series – 1995-2012
• Landings Data: 2J3K - 1981-2012
Prior Distributions
Non-informative priors with relatively wide distributions were used for catchability (q),
observation and process errors. Priors for observation error were limited to an upper bound at 3
times the CV for each index (Swain et al. 2009). The lower bound was set to zero. Sigma
(process error) was allowed to vary between 0 and 1 (Table 1).
Vague priors were also used for carrying capacity (K) and the intrinsic rate of population
increase (r; Table 1). Typically, K is set to the stock biomass in the year prior to the onset of
fishing (P0; Meyer and Millar 1999a). However, in the models used here, the stock biomass in
1981 was not assumed to be the virgin biomass. This may or may not have been the case but,
since it is impossible to know for certain, P0 was allowed to vary between 0.5 and 1 (i.e., initial
biomass was allowed to vary between K/2 and K).
A lognormal distribution for K was specified with a mean of 6000 t and a standard deviation of
3000 t and was limited to between 1000 t and 12000 t for this DU. The distribution was set to
encompass a very wide range of possible values of K while remaining semi-informative. The
mean estimate was based on the survey data (~2000 t higher than the highest historical
estimate) while allowing an extremely wide distribution.
Similarly, the prior for r was set using a mean with a wide lognormal distribution. For this DU, r
was set at µ=0.2 and std=0.15, and restricted to values between 0.001 and 3.0. All prior
distributions are given in Table 1, with posterior results in Table 2.
REFERENCE POINTS
Under the DFO Precautionary Approach (PA) framework, the Critical, Cautious, and Healthy
stock status zones are defined by the Limit Reference Point (LRP) and an Upper Stock
Reference (USR). In situations where there is insufficient information to determine stock
biomass from an analytical model, an empirical approach can be used to identify proxies that
are appropriate to defining PA reference points. For Smooth Skate, a BMSY proxy (biomass
giving maximum sustainable yield) was derived from the DFO fall multispecies RV survey series
(1981-2012). Empirically derived reference points were based on the geometric mean of
1981-88: a period of higher productivity.
COMMERCIAL FISHERIES REMOVALS
Fisheries data available in the NL Region include the Newfoundland Fisheries Observer
Program (NFOP) database, which contains set-by-set information collected at sea in a
standardized format by trained Canadian Fisheries Observers. NFOP Smooth Skate bycatch
data from 2000-12 were used; albeit length frequencies were never collected from Div. 2J3K. A
second source of fisheries data was the DFO-NL Zonal Interchange Format (ZIF) database,
created in 1985 to record commercial landings reported by Canadian fishers (as recorded in
their logbooks and on fish plants’ purchase slips). It must be noted that bycatch of non-
8. 4
commercial species and discards (even of target species) are never reported to DFO-NL
Statistics Branch (for ZIF), nor to the Northwest Atlantic Fisheries Organization (for NAFO
databases). Therefore, NFOP data constitutes the only reliable source of bycatch of non-
commercial species and discarding at sea.
To estimate total bycatch of Smooth Skate in various Div. 2J3K fisheries, a method based on
Kulka et al. (2006) was used with the NFOP and DFO-NL ZIF databases for 2000-12. For each
fishery, reported landings of the target species (in ZIF-NL; summed by year) by fishing vessel
size category was divided by the observed kept weight of this target species per vessel category
by year (e.g., Greenland Halibut, Reinhardtius hippoglossoides; Northern and Striped Shrimp,
Pandalus borealis and P. montagui; Atlantic Cod, Gadus morhua). This factor was then
multiplied by the observed catch weight (=kept+discards) of Smooth Skate per vessel category
in each fishery by year; in order to “bump up” this species’ bycatch estimates to the entire
fishery. Although this method proved useful, very low to no Observer coverage of certain
fisheries precluded its application to particular years or to low/no-coverage fisheries in
Div. 2J3K. Therefore, total removals of Smooth Skate could not be estimated for every fishery
conducted in Div. 2J3K.
To estimate relative fishing mortality, the ratio of estimated commercial landings (all fisheries
combined) to research survey biomass estimates was calculated for each year over 2000-12.
RESULTS AND DISCUSSION
DISTRIBUTION AND HABITAT ASSOCIATIONS
Survey Catch Distribution
Recent fall survey catch rates (2009-12) in the Funk Island Deep DU are shown in Figure 1, and
are consistent with previous time periods (see Simpson et al. 2011a). Higher catch rates
occurred in deeper troughs adjacent to Hamilton Bank, Belle Island Bank, and the Funk Island
Bank. Smooth Skate are often found in deeper and broader water layers (200-600 m) in this DU,
and are infrequently recorded in tows below 800 m. Smooth Skate were also found over a
similar range of water temperatures throughout the Funk Island Deep DU, and over the entire
survey time series. In Div. 2J3KL, Smooth Skate are most often captured in waters ranging from
1.3 ˚C to 3.5 ˚C (Simpson et al. 2011).
As previously established (Kulka et al. 2006; Simpson et al. 2011a), Smooth Skate appear to be
temperature seekers, and are constrained geographically by the availability of suitable
temperature habitats. Densest concentrations of this species occur in troughs surrounding the
banks, where water temperatures are warmer.
Area of Occupancy
In the Funk Island Deep DU in the fall, area of occupancy peaked in 1982 when Smooth Skate
were found in 38 % of the survey area, but subsequently steadily declined to < 2 % by the year
2000. Over the last decade, area of occupancy generally increased, reaching an average of
7.7 % over 2007-12 (Fig. 2). The estimate of At in 2012 was 5.9 %.
ABUNDANCE
Catchability of skate species (including Smooth Skate) by research bottom trawls has been
considered low, given the bottom-dwelling nature of this group. Skates of all sizes have been
observed to flatten into the substrate when fishing gear approaches, and escape under the
trawl’s footrope. Consequently, indices from bottom trawl surveys likely underestimated the
9. 5
presence of Smooth Skate to a large extent. It should be noted that previous comparisons of
catch by Engel and Campelen trawls prior to, and immediately after, the survey gear change in
1995 suggested that catchability was higher for all size classes with the Campelen trawl. The
Engel trawl captured almost no skates < 26 cm, while the Campelen frequently caught skates in
that size range. Therefore, catchability of small Smooth Skate (< 26 cm) between both trawl
types cannot be compared using available survey data. Hence, estimates of biomass and
abundance presented in this paper must be viewed as minimum values. In addition, estimates
of survey catch rate and abundance for this species in the periods prior to and post-gear change
are on different scales.
For all size classes combined, mean number per tow (Fig. 3), and mean weight per tow (Fig. 4)
declined precipitously through the Engel survey period. Similar trends were observed for
estimates of relative abundance (Fig. 5) and relative biomass (Fig. 6). From 1995 to present
(Campelen surveys), indices have varied without trend, and remained low. Both mean number
per tow and relative abundance peaked in 2010, before declining to values similar to those
observed for 1995-2009.
In the Funk Island Deep DU, Engel catch rates displayed similar temporal patterns for immature
and mature Smooth Skate, in addition to relative abundance, but Campelen catch rates were
higher for immature skates (Figs. 7 and 8). Mean catch rates in this DU (Engel surveys) peaked
in 1983 for both immature (0.4 fish/tow) and mature (0.6 fish/tow) skates; then declined in both
cases to relatively low values until 1994 (< 0.03 fish/tow). Catch rates remained at similar levels
throughout the Campelen surveys (1995 onwards).
Abundance estimates of immature and mature Smooth Skate in the Funk Island Deep DU
declined through the 1980s and early 1990s (Engel surveys), remained relatively low and stable
through the mid-1990s to early 2000s (Campelen surveys); then abundance of immature
Smooth Skate began to increase in recent surveys (Fig. 8). Abundance peaked at
approximately 1.9 million immature (1983) and 2.7 million mature (1983) Smooth Skate, then
declined to 0.14 million immature and 0.04 million mature (1994) individuals just prior to the
survey gear change. Campelen survey estimates for both immature and mature components of
the population in this DU have varied without trend from 1995 to 2009, averaging 380,000, and
90,000 individuals, respectively.
SURPLUS PRODUCTION MODELLING
Overall, diagnostics showed a relatively good fit for the model, with good convergence and
reasonable posterior distributions (Table 2). However, concerns with respect to the accuracy of
the landings data used in the model, and the unusually large process error (twice the
observation error), resulted in rejection of the model for Smooth Skate in the Funk Island Deep
DU. Further results or projections are therefore not presented.
REFERENCE POINTS
A BMSY proxy (biomass giving maximum sustainable yield) was derived from the DFO fall
multispecies RV survey series (1981-2012). The empirically derived reference points were
based on the geometric mean of 1981-88 RV survey series biomass estimate which was
considered a period of higher productivity.
The default PA reference points calculated were 40 % BMSY (LRP) and 80 % BMSY (USR)
(Fig. 9). The recent stock size averaged 18 % of the limit reference point over 2008-12 (Fig. 10).
10. 6
COMMERCIAL FISHERIES REMOVALS
Although total mortality was high during the period of decline, it is not possible to determine
sources of this mortality. No directed fishery for Smooth Skate has occurred in Newfoundland
and Labrador waters. However, bycatch estimates of Smooth Skate in various Canadian 2J3K
fisheries over 2000-12 suggest that commercial removals of this species in this DU are low. For
fisheries with Observers’ data, the Greenland Halibut (turbot) fixed gillnet fishery using 0-149.9 t
vessels caught 0.9-3 t of Smooth Skate over 2000-03 and 5 t in 2010, with negligible amounts in
the remaining years (Fig. 11). The Greenland Halibut bottom trawl fishery, using 150-2000+ t
vessels, bycaught 0-0.4 t of this species; while the Northern Shrimp fishery, with 0-149.9 t
vessels and trawl-mounted groundfish excluders (i.e., Nordmore grate), caught 0-0.5 t of
Smooth Skate during this period. Bycatch of this species appeared negligible in the Northern
Shrimp fishery using 150-2000+ t vessels and groundfish excluders, and also in the Snow Crab
(Chionoecetes opilio) pot fishery. Overall, relative fishing mortality, calculated as the ratio of
estimated commercial landings to estimated research survey biomass, averaged 0.0085 over
2000-12 (Fig. 12).
CONCLUSION
Extensive declines in abundance and area of occupancy were observed for both juveniles and
adults in the Funk Island Deep DU during the 1980s and 1990s. However, this DU has shown
some stability since the mid-2000s, with modest increases in area of occupancy in recent years.
The period of decline in the Funk Island Deep DU corresponds to the coldest water
temperatures in this area (Colbourne et al. 2006). In addition, a comparison of rates of decline in
areas of intense commercial trawling with those in areas of no trawling indicated no difference in
decline rates of relative abundance of Smooth Skate (Kulka et al. 2006). Although commercial
fishing removals may have contributed to population decline for this species, the lack of
recovery during the 1990s following a warming period, plus apparently low fishing pressures
observed since the late 1990s, suggests that factors other than fishing are driving the dynamics
of Smooth Skate populations in Newfoundland and Labrador waters.
A BSP was fit to the data from the Funk Island Deep (1981-2010). BSP model diagnostics and
fit to the survey indices appear to be reasonable for both time series over 1981-2010. In
addition, there is no trend in process error in the model. However, there is sufficient process and
observation error in the model to limit the use of long term projections, as indicated by the very
wide credible intervals in the model projections.
SOURCES OF UNCERTAINTY
Several aspects of the current assessment of Smooth Skate in the Funk Island Deep DU remain
uncertain; largely due to partial knowledge about population structure, dynamics, and biology.
Hence, interpretation of the results in this paper should be undertaken judiciously.
Inclusion of new sampling strata and changes in gear type (and selectivity by fish size) in
different survey periods make it difficult to assess spatial and temporal trends in abundance and
distribution, the relationship between spawning population and recruits, and changes in survival,
growth rate, and age structure over more than a few generations.
In addition, information on threats related to commercial fisheries was recently limited by low
Observer coverage of only several fisheries for this DU, with no length frequencies collected at
sea; thereby rendering it difficult to estimate the impact of bycatch mortality on abundance and
population structure.
11. 7
ACKNOWLEDGMENTS
We thank Fisheries and Oceans Canada staff who participated in Canadian research surveys,
and Canadian Fisheries Observers who collected data and specimens aboard commercial
vessels under difficult conditions over many years; thereby allowing us to estimate trends and
examine various biological aspects of Smooth Skate.
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13. 9
Table 1 Priors for parameters used in the surplus production model for Smooth Skate
Parameter Description Prior Distribution
K Carrying Capacity LN (µ=6000t, sd=3000t)
r Population growth rate LN (µ=0.2, sd=0.15)
q.eng Catchability, Engels Trawl Series Norm(1,0.25)
q.cam Catchability, Campelen Trawl Series Norm(1,0.25)
Sigma Process error U(0,1)
tau.eng Observation error, Engels Trawl Series U(0,2.39)
tau.cam Observation error, Campelen Trawl Series U(0,1.99)
14. 10
Table 2 Summary of parameter estimates using a Bayesian surplus production model for Smooth Skate
in the Funk Island Deep DU
Parameter Description Posterior (median, 95% CI)
K Carrying Capacity 4749.00 (2189.87 – 10070.25)
r Population growth rate 0.10 (0.03 – 0.28)
q.eng Catchability, Engels Trawl Series 0.69 (0.35 - 1.38)
q.cam Catchability, Campelen Trawl Series 1.03 (0.49 – 2.12)
Sigma Process error 0.61 (0.38 – 0.89)
tau.eng Observation error, Engels Trawl Series 0.32 (0.02 – 0.76)
tau.cam Observation error, Campelen Trawl Series 0.36 (0.03 – 0.80)
MSY Maximum Sustainable Yield 120.45 (32.39 – 411.00)
FMSY F at MSY 0.05 (0.02 – 0.14)
BMSY Biomass at MSY 2374.00 (1094.95 – 5034.17)
DIC Deviance Information Criteria 333.8
15. 11
Figure 1 Numbers per tow of Smooth Skate caught in DFO fall research surveys conducted in the Funk
Island Deep DU, 2009-2012
16. 12
Figure 2 Area Occupied by Smooth Skate in DFO fall research surveys in the Funk Island Deep DU,
1981-2012. Note the change in survey gear from Engel to Campelen trawl in 1995
17. 13
Figure 3 Mean number per tow of Smooth Skate in DFO fall research surveys in the Funk Island Deep
DU, 1981-2012. Note the change in survey gear from Engel to Campelen trawl in 1995
18. 14
Figure 4 Mean weight per tow (kg) of Smooth Skate in DFO fall research surveys in the Funk Island Deep
DU, 1981-2012. Note the change in survey gear from Engel to Campelen trawl in 1995
19. 15
Figure 5 Abundance index for Smooth Skate in DFO fall research surveys in the Funk Island Deep DU,
1981-2012. Note the change in survey gear from Engel to Campelen trawl in 1995
20. 16
Figure 6 Biomass index (tons) for Smooth Skate in DFO fall research surveys in the Funk Island Deep
DU, 1981-2012. Note the change in survey gear from Engel to Campelen trawl in 1995
21. 17
Figure 7 Mean number per tow of immature (< 48 cm) and mature (≥ 48 cm) Smooth Skate in DFO fall
research surveys in the Funk Island Deep DU,1981-2009. Sampling by size was not conducted in
2010-12
22. 18
Figure 8 Index of abundance (000s) of immature (< 48 cm) and mature (≥ 48 cm) Smooth Skate in DFO
fall research surveys in the Funk Island Deep DU, 1981-2009. Sampling by size was not conducted in
2010-12
23. 19
Figure 9 Plot of the BMSY proxy and proposed PA reference points for Smooth Skate in the Funk Island
Deep DU. Unit for biomass index is tonnes. Note the change in research survey gear from Engel to
Campelen trawl in 1995
24. 20
Figure 10 Plot of Biomass relative to the LRP for the Funk Island Deep DU. Note the change in research
survey gear from Engel to Campelen trawl in 1995
25. 21
Figure 11 Bycatch estimates (kg) of Smooth Skate by observed fishery in the Funk Island Deep
designatable unit, 2000-12. Data are from Canadian Fisheries Observers and DFO-NL ZIF
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
5,500
2000 2002 2004 2006 2008 2010 2012
Year
SmoothSkateBycatchEstimates(kg)
Greenland Halibut gillnets_VC 1-3
Greenland Halibut trawls_VC4-7
Shrimp trawls_VC 1-3
Shrimp trawls_VC 4-7
Snow Crab pots_VC 1-3
26. 22
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
2000 2003 2006 2009 2012
CommercialLandings/SurveyBiomass
Figure 12 Relative fishing mortality estimates (commercial fishery landings relative to research survey
biomass) in the Funk Island Deep designatable unit, 2000-12