Changes in the Euro‐Atlantic fish species composition resulting from fishing and ocean warming

Abstract

Studies of actual ichtyological biodiversity in the European Atlantic Ocean and estimation of changes in the relative abundance of fish species in catches off Arcachon, on the shelf and in the Bassin d'Arcachon, from 1727 to the present day are made. These show that some previously dominant species are now rare. Several disappeared to the south of the Bay of Biscay, such as the bottom-living elasmobranchs with low reproduction rates (Echinorhi- nus brucus, Squatina squatina, Raja batis, R. brachyura, R. clavata, Dasyatis pastinaca, Myliobatis aquila, Galeorhinus galeus, Mustelus asterias), and teleostean fishes Trigla lyra andEutrigla gurnardus. Overfishing with most fishing gears, but especially bottom trawls is responsible for their reduction. An additional study was made on tropical species which were not recorded before 1950 to the north of Portugal. The species include

Artisanal fisheries and reproductive biology of the golden cownose ray, Rhinoptera steindachneri Evermann and Jenkins, 1891, in the northern Mexican Pacific

“…In the North Sea, fishing mortality has dramatically altered species composition of the local skate assemblage (Walker and Hislop, 1998;Dulvy et al, 2000). Declines of large myliobatiform rays also have been reported from the Bay of Biscay (Quero, 1998) and populations of Dasyatis spp. and Aetobatus narinari off Calicut, India were greatly reduced in the late tality from the shrimp fishery possibly exceeding that from directed elasmobranch fisheries (Márquez-Farías, 2002).…”

Extinction, survival or recovery of large predatory fishes

“…Often these species are not target species, but caught as bycatch, so their disappearance is rarely noted. For example, 14 species of large elasmobranchs disappeared from the Gulf of Lions (northwest Mediterranean) from trawl surveys between 1957 and 1995 (Aldebert 1997), and nine species of elasmobranchs have disappeared from the Bay of Biscay since 1727 (Quero 1998). Similarly, the near extinctions of two formerly common skate species in the northwest Atlantic (Casey & Myers 1998) and Irish Sea (Brander 1981) were only recognized many years later.…”

Effect of temperature on maximum swimming speed and cost of transport in juvenile European sea bass (Dicentrarchus labrax)

“…In the case of sea bass, the deficiency in basic information is striking, particularly when it comes to defining environmental tolerances and physiological optima. In recent years a progressive northward spread of sea bass has been recorded along the western coasts of Europe; this expansion is believed to be related to the warming of the European Atlantic waters (Quéro, 1998;Quéro et al, 1998;O'Brien et al, 2000;Stebbing et al, 2002). As the northern limits to the ranges of the species extend further, the effect on the fisheries is likely to be important but remains very difficult to predict.…”