Overfishing aff inherency

Fish-Mid-trophic

Overfished species are especially key to marine ecosystems because they are typically mid-trophic species

(Morten, Martin Edwards, Anthony J. Richardson, Nicholas C. Halliday, Sarah Wanless, “From plankton to top predators: bottom-up control of a marine food web across four trophic levels.”, Journal of Animal Ecology. Nov2006, Vol. 75 Issue 6, p1259-1268. 10p. 1 Chart, 3 Graphs, 1 Map, EBSCO)

Many marine ecosystems are dominated by a few abundant mid-trophic species. usually pelagic schooling fish, with higher diversity at lower and higher trophic levels (Rice 1995). Such species channel energy and nutrients from plank tonic primary and secondary producers to top predators. and thus play an important role in regulating ecosystem dynamics. One of the species occupying this trophic position in the North Sea is the lesser sandeel (Anunod vies nlcirinus R.aitt hereafter sanded), which feeds on zooplankton (mainly copepods)(Reay 19X6)and is a key prey of predatory fish, marine mammals and seabirds Greenstreet, McMillan & Armstrong 199g: Homes & Bergstad 1999: Adlerstein & Welleman 2000: Furness 2002). In particular. the large breeding populations of seabirds in the NW North Sea (East coast of Scotland) depend extensively on sandeels (Wanless. Harris & Greenstreet 199g: Furness & Tasker 2000). Since the 1970s. sandeels have been among the dominant mid-trophic pelagic fish in the North Sea. Because of their specific habitat requirements sandeels have a patchy distribution and exhibit strong population structure within the North Sea (Pedersen. [.ewv & Wright 1999). Starting in the I950s. a Large industrial fishery for fishmeal and tìshoil developed. which in the I980s and I990s was the largest single-species fishery in the region with landings in some years exceeding I million tonnes (Furness 1999). There are several indications that sandeels have been less abundant in the North Sea in the last few years than previously. In 2004 seabirds in this area experienced the worst breeding season on record. linked probably to a lack of suitable food. i.e. sandeels (Harris et aL 2004: Mayor e, aL 2005). Similarly, in 2003 and 2004. landings from the industrial sanded fishery were less than 50% of the average, indicating repeated recruitment failure since 2001 (ICES 2004). In July 2005 the fishery was suspended following greatly reduced land ings. and only a limited fishery effort has been allowed initially in 2006 (Anonymous 2005).

Sharks

Sharks are often killed as by-catch

(Beth A., UCN Species Programme/Conservation International Global Marine Species Assessment, Biological Sciences, Old Dominion University, Norfolk, Cristiane T. Elfes, IUCN Species Programme/Conservation International, Biodiversity Assessment Unit, Jonnell C. Sanciangco, UCN Species Programme/Conservation International Global Marine Species Assessment, Biological Sciences, Old Dominion University, Helen Pippard, IUCN Regional Office for Oceania, Kent E. Carpenter, IUCN Species Programme/Conservation International Global Marine Species Assessment, Biological Sciences, Old Dominion University, “Conservation Status ofMarine Biodiversity in Oceania: An Analysis of Marine Species on the IUCN Red List of Threatened Species.”, Journal of Marine Biology. 2011, Vol. 2011, p1-14. 14p. 1 Chart, 4 Maps, p 6-7, EBSCO)

Approximately one-fourth of all sharks and batoids found in Oceania are in threatened categories. Like sea turtles, the threats to the majority of these species occur globally, and only 10 of the 97 species of sharks and rays present in Oceania are endemic to the region. The primary threat to sharks and rays (batoids) is their capture in nets from both targeted and accidental catch. Most shark species grow slowly, mature late, produce few young, and have low rates of population increase, making them highly vulnerable to depletion with a low capacity for recovery from over- exploitation [321. Shark fisheries have proliferated around the world during recent decades, in response to increasing demand for shark products and as traditional fisheries come under stronger management. Millions of sharks are caught each year for their fins which are used to make the Asian delicacy shark fin soup 1341. Many subsistence and small-scale fisheries for sharks occur in the Oceania region. Typically, the meat is used for domestic consumption and the teeth and jaws are sold as curios in the tourist industry [471; however, catches are poorly documented. Sharks are also commonly taken in the Oceania region as by-catch of commercial tuna and other pelagic long-line or purse seine fisheries, which retain primarily shark fins for the international trade [47—491. The two most threatened shark and ray species found in Oceania, Harrison’s Deepsea Dog fish (Centrophorus harrissoni) and the Narrowsnout Sawfish (Pristis zijsron). both listed as Critically Endangered, have ranges primarily outside of the region, but with records from a few locations within Oceania including New Caledonia and Approximately 25% (19 of 75 species) of sharks and 80% (4 of 5 species) of chirnacras are listed as Data Deficient. For many shark species, little is known about their reproductive biology and quantitative data is lacking on the impact of fisheries on their populations. For example, approximately 50% of the estimated global catch of chondrichthyans is taken as by-catch which does not appear in official fishery statistics and is rarely managed 1501. Most chirnaeras are not well-studied, as they are primarily deep-water species that occur in temperate waters. For the few species that are thought to occur in Oceania, little is known about their distribution, reproduction, or the potential impact of fishing activities on their populations. Fiji.

Sea Turtles

Sea turtles are endangered by overfishing

(Beth A., UCN Species Programme/Conservation International Global Marine Species Assessment, Biological Sciences, Old Dominion University, Norfolk, Cristiane T. Elfes, IUCN Species Programme/Conservation International, Biodiversity Assessment Unit, Jonnell C. Sanciangco, UCN Species Programme/Conservation International Global Marine Species Assessment, Biological Sciences, Old Dominion University, Helen Pippard, IUCN Regional Office for Oceania, Kent E. Carpenter, IUCN Species Programme/Conservation International Global Marine Species Assessment, Biological Sciences, Old Dominion University, “Conservation Status ofMarine Biodiversity in Oceania: An Analysis of Marine Species on the IUCN Red List of Threatened Species.”, Journal of Marine Biology. 2011, Vol. 2011, p1-14. 14p. 1 Chart, 4 Maps, p 6-7, EBSCO)

3.2. Highly Migratory and Wide-Ranging Specks. Comprehensive assessments were completed for all sea turtles, sharks and rays, marine mammals, and sea birds in the region. Among these, sea turtles have the highest pro.- portion of threatened species of any group, with all five of the species present in Oceania, Loggerhead (Careno careno), Green (Chelonia mydas), Leatherback (Derrnoclielys coriacea), Hawksbill (Eretrnochelys itnbricata), and Olive Ridley (Lepidochelys olivacea), listed in threatened categories. Threats to all sea turtle species occur globally and at all stages of their life cycle. Marine turtles lay their eggs on beaches, which are subject to threats such as coastal development and sand mining. The eggs and hatchlings are threatened by pollution and predation by introduced predators such as pigs and dogs, as well as collection by humans. Sea turtles have traditionally been used in the Pacific Island for their meat and eggs, their shells used for decoration, fishing lures and hooks, and for sale and opportunistic by-catch by fishers targeting shellfish and sea cucumbers [40—431. At sea, marine turtles are faced with threats from targeted capture in small-scale subsistence fisheries, by-catch by long-line and trawling activities, entanglement in marine debris, and boat strikes. Their life history characteristics, particularly late sexual maturity and long juvenile stage, combined with the many threats from human activities in the sea and on land contribute to their high risk of extinction [34J. In addition, global climate change is now considered to be a serious, if not entirely understood, threat that is contributing to the loss of nesting beaches [441. possibly skewed sex ratios L41,and loss of foraging grounds [46].