This study examined the population characteristics of horn sharks (Heterodontus francisci) along the coast of Carpinteria and the Northern Channel Islands in California. A total of 109 horn sharks were collected and measured from these areas between May and August 2004. The results showed a female-biased sex ratio of 1.4:1 across all sites. No significant differences were found in size or weight between sharks at island versus mainland sites. For male sharks, clasper length was found to increase rapidly with total length, indicating sexual maturity is reached at approximately 625 mm in total length.
The First Confirmed At-Sea Sighting of Longman’s Beaked Whale (Indopacetus pa...Teresa Martin
The Longman's beaked whale (Indopacetus pacificus) is a rare species that is thought to primarily inhabit deep waters in the Indian and Pacific Oceans. During a seismic survey in late 2014, a group of approximately twenty Longman's beaked whales were encountered in Kenyan waters. To our knowledge this was the first at-sea sighting for this species in the Kenyan Economic Exclusion Zone (EEZ) to date. Here we present information and identification photographs pertaining to this sighting.
The First Confirmed At-Sea Sighting of Longman’s Beaked Whale (Indopacetus pa...Teresa Martin
The Longman's beaked whale (Indopacetus pacificus) is a rare species that is thought to primarily inhabit deep waters in the Indian and Pacific Oceans. During a seismic survey in late 2014, a group of approximately twenty Longman's beaked whales were encountered in Kenyan waters. To our knowledge this was the first at-sea sighting for this species in the Kenyan Economic Exclusion Zone (EEZ) to date. Here we present information and identification photographs pertaining to this sighting.
Presentation to the Canadian Department of Fisheries and Oceans expert committee assessing the effectiveness of current mitigation guidelines for seismic surveys (oil and gas exploration at sea).
Bathymetric distribution concerns to the vertical range of organisms in space i.e. from the high Alpine peak to the abyssal depth of the sea. Primary conditions affecting, Three organic realms of bathymetric distribution of animals
МЫ ПРЕДЛАГАЕМ ЛУЧШИЕ МЕЖДУНАРОДНЫЕ ПРАКТИКИ В ОБЛАСТИ РАЗВИТИЯ ПРЕДПРИНИМАТЕЛЬСТВА
IEEAcademy осуществляет свою деятельность в рамках ФЕДЕРАЛЬНОГО ЗАКОНА ОБ ОБРАЗОВАНИИ В РОССИЙСКОЙ ФЕДЕРАЦИИ N 273-ФЗ от 29 декабря 2012 года.
И призвана развивать и коммерциализировать экспертные компетенции в формате коротких сфокусированных образовательных программ.
Наши эксперты-преподаватели это первые лица компаний и уникальные специалисты, обладающие практическим опытом успешной реализации проектов в своем кластере.
Presentation to the Canadian Department of Fisheries and Oceans expert committee assessing the effectiveness of current mitigation guidelines for seismic surveys (oil and gas exploration at sea).
Bathymetric distribution concerns to the vertical range of organisms in space i.e. from the high Alpine peak to the abyssal depth of the sea. Primary conditions affecting, Three organic realms of bathymetric distribution of animals
МЫ ПРЕДЛАГАЕМ ЛУЧШИЕ МЕЖДУНАРОДНЫЕ ПРАКТИКИ В ОБЛАСТИ РАЗВИТИЯ ПРЕДПРИНИМАТЕЛЬСТВА
IEEAcademy осуществляет свою деятельность в рамках ФЕДЕРАЛЬНОГО ЗАКОНА ОБ ОБРАЗОВАНИИ В РОССИЙСКОЙ ФЕДЕРАЦИИ N 273-ФЗ от 29 декабря 2012 года.
И призвана развивать и коммерциализировать экспертные компетенции в формате коротких сфокусированных образовательных программ.
Наши эксперты-преподаватели это первые лица компаний и уникальные специалисты, обладающие практическим опытом успешной реализации проектов в своем кластере.
08.Snapper Fish.pdf. Snapper fish stand out as prized species in the realm of...Saiqa Riaz
❑ Snapper fish belong to the family
Lutjanidae and are widely distributed in
tropical and subtropical waters around
the world.
❑ Characterized by their streamlined
bodies, large eyes, and sharp canine
teeth
❑ They play a crucial role in marine
ecosystems as both predators and prey.
▪ Snapper species vary in size, with some
reaching lengths of over three feet and
weights exceeding 50 pounds
many snapper species are commonly found in
shallow coastal waters at depths ranging from 10 to 100
meters.
▪ Some species can inhabit deeper offshore environments
exceeding 200 meters.
Morphology of snapper fish
1. Body Shape and Size:
Have sleek, torpedo-shaped bodies that are laterally compressed.
Small species measuring a few inches to large species reaching
several feet in length.
2. Jaws and Teeth:
Their mouths are typically terminal.
Carnivorous snapper species often have conical teeth for grasping
and puncturing prey
Omnivorous species may have more flattened teeth for crushing
shells or grinding plant material.
3. Fins and Scales: several fins contribute to their locomotion,
stability.
Two dorsal fins, one near the head
another closer to the tail, along with anal,
Pectoral, and pelvic fins
Covered in overlapping scales
That provide protection against abrasion,
Predators, and pathogens.
Conclusion
Snapper fish stand out as prized species in the realm of seafood,
cherished for their delectable taste, firm texture, and vibrant colors.
Their streamlined bodies and sharp teeth reflect their predatory nature,
Play a vital roles within marine ecosystems.
Their popularity among anglers and consumers has led to concerns
regarding overfishing and habitat degradation, prompting the
implementation of management measures to ensure their long-term
sustainability.
Despite these challenges, the allure of snapper fish persists, captivating
both culinary enthusiasts and conservationists alike with their culinary
excellence and ecological significance.
Puffer fish belonging to the family tetraodontidae are usually distributed in the shallow waters. During investigation in stations viz. Marina Park, Chidiyatapu and Burmanullah, around Andaman, five species from genus Arothron and two from Canthigaster have been recorded and were mostly found to prefer coral reefs and rock crevices, with the exception of Arothron immaculatus, which was found to be present in the open waters and it confined to sandy bottom substrate with patches of sea grasses around them. These fishes were found to be most diverse and abundant in Chidiyatapu with the Margelef’s Richness Index of 2.49, Shannon-Wiener index of 1.05 and Pielou’s evenness index of 0.96. Biometric analysis results demonstrate that they have shown an isometric growth. The individuals collected were mostly lying in the length group of 120-160 mm. Gut content analysis of A. Immaculatus reveals that the fish feed mainly on molluscs and sea urchin and the other food items were shrimps, crabs, sponges, micro algae, foraminiferans etc. gastro-somatic index, hepato-somatic index and gonado-somatic indices were also calculated to throw light upon the feeding behavior and reproductive maturity of the fishes. Most of the individuals were found to be in the developing stage of maturity.
Shark introduction Morphology and its behaviour characteristicsArubSultan
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the Batoidea (rays and kin). Some sources extend the term "shark" as an informal category including extinct members of Chondrichthyes (cartilaginous fish) with a shark-like morphology, such as hybodonts. They generally do not live in freshwater, although there are a few known exceptions, such as the bull shark and the river shark, which can be found in both seawater and freshwater.Sharks have a covering of dermal denticles that protects their skin from damage and parasites in addition to improving their fluid dynamics. They have numerous sets of replaceable teeth.
Introduction for NOAA lesson by Susan Kaiser, TAS 2012: One Fish, Two Fish skaiser4800
This Power Point introduces the work of marine scientists working for FWC and NOAA as they study fish migration patterns and population off the Florida Keys near the Dry Tortugas. The original presentation was written by Danielle Morley and edited by Susan Kaiser Teacher at Sea, 2012 for use with the lesson she developed called One Fish, Two Fish. All of the resources are available at the NOAA TAS website.
1. POPULATION ASSESSMENT OF THE HORN SHARK, HETERODONTUS
FRANCISCI, ON ROCKY REEFS IN CARPINTERIA AND THE NORTHERN
CHANNEL ISLANDS, CALIFORNIA.
Hoobler, S. M. Marine Science Institute, University of California Santa Barbara.
4. Results
Figure 1. Total length–frequency distributions
of female and male H. francisci used in study.
Figure 2. Length–weight relationship of H.
francisci across all study sites. N = 109
Figure 3. Relationship between total length
(mm) and inside clasper length (mm) for
males across all stages of maturation. N = 45
1. Introduction
The horn shark, Heterodontus francisci, is a small near-
shore rocky reef shark that ranges from central California
to the Gulf of California. Santa Barbara county and the
Northern Channel Islands are at the northern extension of
their known range. The horn shark is nocturnal and
actively feeds at night on invertebrates and small fishes.
Although there is no commercial value for this shark, they
are often taken as by-catch in trawls and occasionally by
recreational fishermen. In recent years, they have been
maintained in public aquariums and are sold commercially
to private aquarium collectors.
Very little information has been collected regarding the age
and growth of horn sharks. Additionally, studies to date
have made general inferences as to horn shark size at
sexual maturity. Here I present the results to date a study
that is designed to gain information on life history
characteristics of this local population including: age,
growth, size of sexual maturity, and population structure at
Carpinteria, Anacapa Island, and Santa Cruz Island,
California.
2. Research Questions
1. What is the sexual distributions of H. francisci found at
Carpinteria, Anacapa Island, and Santa Cruz Island?
2. Is there a difference in size structure of sharks found at
island sites or mainland sites?
3. At what size does a male horn shark sexually mature in
relationship to total length and clasper length?
3. Methods
• 109 Horn sharks were collected by
SCUBA divers off the coast of Carpinteria,
Anacapa Island, and Santa Cruz Island
between May and August 2004.
• Data collected on all sharks consisted of
sex determination, length, weight, GPS
location, and presence of ectoparasites.
• Male sharks had their claspers measured
and were checked for the presence of
calcified claspers, rhipidion, and if their
siphon sac inflated.
• All sharks were tagged and released in the
area of capture.
Horn Shark Total Length vs. Inside
Clasper Length
y= 2.5788e0.0052x
R2
= 0.9284
15
65
115
165
325 425 525 625 725 825
Total Length (mm)
InsideClasperLength
(mm)
Juvenile
Adults
Transitional
Length Frequency Histogram of Male
and Female Horn Sharks
0
5
10
15
20
300 350 400 450 500 550 600 650 700 750
Length (mm)
Frequency
Females n= 63
Males n= 45
Length vs. Weight
y = 0.0572e0.0057x
R2
= 0.9343
0.00
1.00
2.00
3.00
4.00
5.00
6.00
200 400 600 800 1000
Shark Total Length (mm)
SharkWeight(kg)
Anacapa Island
Carpinteria
Santa Cruz Island
5. Conclusions
• The pooled ratio of females to males indicates a bias
towards females (1.4:1) across all sites (Fig. 1).
• Sharks found at mainland and island sites (Fig. 2) are
significantly similar in length and weight (P < 0.001).
• There is a significant relationship between clasper
growth and total length of sharks (P < 0.0001).
Claspers of male horn sharks rapidly increase in length
as they approach maturation at approximately 625 mm
TL (Fig. 3). Claspers were fully calcified, rhipidions
were calcified and opened, and siphon sacs inflated
between 675 and 780 mm TL.
6. References
Ebert, D A 2003. Sharks, Rays, and Chimaeras of
California. pp.81-86. Berkeley and Los Angeles, CA:
University of California Press.
Sergio et al. 2001. Reproductive biology of the Caribbean
sharpnose shark, Rhizoprionodon porosus, from
northern Brazil. Mar. Freshwater Res. 52: 745 – 752.
Strong, W R, Jr. Behavioral ecology of horn sharks,
Heterodontus francisci, at Santa Catalina Island,
California, with emphasis on patterns of space utilization.
MS. California State University, Long Beach, 1989. 265
pp. Advisor: Nelson, D.R.
7. Acknowledgements
This study was funded by a grant from PADI Project
Aware. Thanks are extended to Dr. Jenn Caselle for her
constructive comments and support. Additionally, thanks
are extended to the UCSB PISCO Subtidal team for
helping with shark collections.