This Earth Day, remember the deep-sea. The goblin shark (shown here) and the frill shark are two of the rarest and deepest dwelling of sharks. Only two of each species have been taken in North America EVER. That’s why researcher Jose Castro from Mote Marine Laboratory was surprised when Japanese friends set up a trip to nearby Chiba, where a few goblins are taken each year. Dr. Castro says he saw more rare deep water sharks in Chiba in one day than he has ever seen in the USA: including Dalatias, Deania, Cihrrigaleus, Etmopterus, Apristurus, etc.
Shark populations are hard hit by commercial fisheries taking shark fins as incidental catch for the Asian soup market. The problem is that the shark fishery is widespread. Recent papers by Julia Baum et al (2003) and Ransom Myers and colleagues (2007) have shown that many shark species off North Carolina have declined precipitously in recent decades, while other shark populations have increased due to predation release. Large sharks prey upon smaller ones. Scalloped hammerheads, white, and tiger sharks have decreased 89%, 79% and 65%, respectively, while other elasmobranch populations, like chain dogsharks and cownose rays have grown. Cownose rays eat bay scallops, unfortunately, so bay scallop populations have been decimated. You can download the paper here.
This research has important policy implications. That’s why Pew Charitable Trusts and the Census of Marine Life are supporting the Global Shark Assessment. From their website:
The potential benefits of shark conservation are great. In protecting a host of large, charismatic, but particularly vulnerable species, shark conservation offers the opportunity to protect not just sharks, but the myriad other species and ecosystems with which and in which sharks interact. Hence, at stake are not merely sharks, but our still vastly misunderstood marine realm.
This work will also fold into a Global Marine Species Assessment (GMSA). The GMSA project will be the first global review of the conservation status of every marine vertebrate species, and of selected invertebrates and plants. The project involves a range of partners in compiling and analyzing all existing data on approximately 20,000 marine species, and will determine the risk of extinction according to the IUCN Red List Categories and Criteria. The theory goes that the listing of endangered species will help to win their protection.
References:
Julia K. Baum, et al. 2003. Collapse and Conservation of Shark Populations in the Northwest Atlantic. Science 299, 389.
Ransom A. Myers et al. 2007. Cascading Effects of the Loss of Apex Predatory Sharks from a Coastal Ocean. Science 315, 1846-1850.
