Conserve Wildlife Blog

Archive for the ‘Fish’ Category

Shark & Ray Conservation Week (Part 3 of a 6-part series – the Sand Tiger Shark)

Tuesday, June 28th, 2016

This story marks the third of six blog stories spotlighting New Jersey’s shark species.


THE SAND TIGER SHARK: PREDATORS EVEN BEFORE THEY’RE BORN

By Michael Davenport, Wildlife Biologist & GIS Manager

Sand tiger sharks look ferocious. With a mouth agape with rows of outward-pointing needle-sharp teeth, they are often regarded as deadly man-eaters. However, their appearance doesn’t tell the whole story. Although they have been known to attack humans, they are not man-eaters. Those needle-sharp pointed teeth are very poor tools for cutting through mammal flesh (unlike the great white’s serrated triangular teeth which are perfect for cutting through mammal flesh). Sand tigers are primarily fish eaters and attacks on humans are often made either when the shark is approached to closely or if a diver happens to be spear fishing and the shark is attempting to catch the speared fish.

A sand tiger shark. Photo courtesy of Gerald Walters & Jenkinson's Aquarium.

A sand tiger shark. Photo courtesy of Gerald Walters & Jenkinson’s Aquarium.

Sand tigers are very ferocious when it comes to eating fish. So ferocious, in fact, that they are known to feed on their siblings even before they are born. Sand tigers give birth to live young. The mother sand tiger has two uterine sections within her body in which up to 50 young sand tigers will develop. As they grow, the larger, stronger sand tiger pups will nourish themselves by feeding on the others. Eventually, only the two young will then be born, already born killers.

To learn more about this shark species which occurs in New Jersey waters, visit our Field Guide page.


 

Shark & Ray Conservation Week (Part 2 of a 6-part series – the Basking Shark)

Monday, June 27th, 2016

This story marks the second of six blog stories spotlighting New Jersey’s shark species.


THE BASKING SHARK: A GENTLE GIANT

By Michael Davenport, Wildlife Biologist & GIS Manager

Just as the largest whales are filter feeders, so are the two largest fish in the world. The basking shark, the second largest fish in the world after the whale shark, grows to a length of up to 33 feet long but feeds on organisms smaller than your fingernail. It swims through the ocean with its mouth open while tons of sea water and the small organisms with in it, enter the mouth and get filtered by the shark’s enormous gills. If you’ve used a pool net to skim leaves and insects off the top of a swimming pool, you have an idea of how the basking shark feeds.

A basking shark feeding. Photo courtesy of Flickr user jidanchaomian.

A basking shark feeding. Photo courtesy of Flickr user jidanchaomian.

Despite their enormous size, basking sharks are harmless to humans. Unfortunately, like many shark species, they are a species in decline. Basking sharks have been hunted as a source of food, fins, and liver oil for many years. They reproduce slowly, so if they are to recover, they will require protection throughout their range for many years.

To learn more about this shark species which occurs in New Jersey waters, visit our Field Guide page.


 

Shark & Ray Conservation Week (Part 1 of a 6-part series)

Sunday, June 26th, 2016

This story marks the first of six blog stories spotlighting New Jersey’s shark species – and educating people about why shark populations are in danger throughout the world.


CONSERVE WILDLIFE FOUNDATION IS INITIATING CONSERVATION EFFORTS DIRECTED AT THE SHARKS, RAYS, AND SKATES WHICH OCCUR IN NEW JERSEY WATERS.

By Michael Davenport, Wildlife Biologist & GIS Manager

Sharks, rays, and skates are cartilaginous fish within the subclass Elasmobranchii. Elasmobranchs predate the dinosaurs by hundreds of millions years, having first appeared in the fossil record during the Devonian Period approximately 400 million years ago. They are a very diverse group, with over 350 species of sharks and over 500 species of rays and skates currently existing worldwide.

A sand tiger shark. Photo courtesy of Gerald Walters & Jenkinson's Aquarium.

A sand tiger shark. Photo courtesy of Gerald Walters & Jenkinson’s Aquarium.

Sharks and rays are highly specialized and occupy a wide variety of habitats. Some species are slow-moving bottom feeders which prey on crustaceans while others are fast-swimming predators of marine mammals. Many shark and ray species are apex predators, at the top of many food chains. They play a critical function within the marine (and occasionally freshwater) ecosystem preying on the weak, sick, or injured and maintaining a balance within their environment.

Sharks and rays are frequently misunderstood and feared as a result. Sharks have been portrayed in movies as man-eating monsters which target humans as a meal. Rays are also feared due to their appearance and because many species do, in fact, carry defensive barbs on their tail which have been known to injure or even kill people.

Because of their bad reputation, sharks are often targeted by recreational fishermen as trophy catches. However, the greatest threat to sharks and rays comes from commercial fishing for several reasons: (1) directed fishing for sharks, especially for their fins; (2) capture as bycatch during other fishing activities; and (3) overfishing of prey species.

Degradation of habitat is another threat to sharks and rays. Many species give birth within inshore coastal waters and those same areas are a nursery for the young. Pollution and/or development of those areas represent a threat to those species during a critical stage of their life. Climate change and its impact on food resources of sharks and rays is another potential major threat to sharks and rays which is poorly understood at this time.

Due to the biology of sharks and rays, these many threats are worsened by the fact that fewer individuals are replaced than are killed. Sharks and rays are generally long-lived species which don’t reach sexual maturity often until they’re in their teens or older. Then, they may give birth to as few as two young every two or three years.

Follow our blog posts throughout the week to learn more about some of the shark species which occur in New Jersey waters.


 

New Jersey’s Status Review of Freshwater Fish

Monday, March 21st, 2016
SEVERAL SPECIES OF FRESHWATER FISH TO RECEIVE IMPERILED STATUS

By Michael Davenport, GIS Program Manager

The New Jersey Division of Fish and Wildlife has recently completed a status review of the freshwater fish species within the state. A total of 53 species were reviewed by a panel of experts and the results of that review were then presented to the Endangered and Nongame Advisory Committee which voted  on March 16th to recommend the status changes. As a result of this status review, ten additional species within the state will be receiving an imperiled status of either Endangered, Threatened, or Special Concern. The date for when those listings will become official is still unknown.

Black-banded sunfish. © Shawn Crouse

Black-banded sunfish. © Shawn Crouse

Conserve Wildlife Foundation of NJ’s online field guide, a one-of-a-kind free reference focused on New Jersey’s wildlife, has expanded to include the additional fish species.

To learn more about these fish species and the threats facing them, please click below to link to our field guide:

 

 

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