Fish from marine reserves are not characteristic caution

One of the species of fish-surgeons ( Naso vlamingii ), the inhabitants of coral reefs. Figure out in Nature

It is known that fish living in marine reserves, the larger and more prolific than their counterparts in unprotected areas. Australian biologists have shown that, in addition, fish from reserves more trusting and therefore easier to catch. And when you consider that the fish constantly slips out of reserves to unprotected waters, this information can serve as an argument in favor of the establishment of marine reserves.

Long time was considered that the protection of individual sections of the World ocean cannot be effective because of its global reach and “openness”. But it gradually became clear that the ocean is not only global but also local effects of man. As examples of the latter can lead to construction in the coastal zone, the deepening of navigation channels, poorly regulated fisheries, wild life, etc. To protect against local influences began to create so-called marine reserves — marine protected area. Now there are more than 3000. One of the main goals of marine reserves is to provide safe and supportive in all respects of space for growing food fish.

Loginoremail that the fish in these reserves live longer, on average, grow to a significant size and leave more offspring than fish in unguarded water areas. It is natural to expect that some fish larvae, and adults, out of the reserves into surrounding unprotected areas. Indeed, the scientists showed that of the reserve located within the Great barrier reef. from 55 to 83% of juvenile percoid distributed around the reserve unguarded waters.

Australian researchers from James cook University recently showed that fish from marine reserves are not only on average older and larger, but also more careless and thoughtless than their neighbors in surrounding unprotected waters. Biologists have conducted research on tropical fish from three families: the fish-parrots. fish-surgeons and fish-butterflies. Parrots and surgeons are a favourite object of fishers who use them for food. Smaller butterfly fish are not culinary object, but they are often used by aquarists because they get along well with other coral fish. Observations were carried out in the Bohol sea near the Philippine archipelago, on the border of three protected areas in the size of 6-10 hectares, within 200 m inside and outside of the boundaries of each protected area. The experimenter was diving with a mask and snorkel, choose fish from the three aforementioned collections, and evenly began to swim towards it at a speed of about 0.75 m/S. Task was to determine the distance between diver and fish, with which this fish started to swim away from the diver or escape. In the article the authors even used a special abbreviation to denote this parameter (FID flight initiation distance). In addition, the authors roughly estimated the size (length) of a fleeing fish.

Fig. 1. The distance from which the fish begins to swim away from approaching divers in the 200 m inside (inside) and exterior (outside) from the boundaries of protected areas. Data for fish-surgeons (a), parrotfish (b) and butterfly fish Grey . black and blue dots correspond to the data for three marine reserves. Drawing from the discussed article in Ecology Letters

It turned out that the distance from which the fish begins to run from the approaching danger, is different in nature reserves and on unprotected territory. The reserve is less than the distance (average 2-3 m) than outside (average 4 m and more); see Fig. 1a, b. This means that in the reserve fish are less cautious and closer let to itself a source of potential danger. Such differences, however, were found only for fish from those two families, which are regularly caught in the gastronomic purposes. For butterfly fish, which are not the subject of gastronomy, these distances were similar in nature reserves and around them (Fig. 1C). The figures given distances adjusted for the size of the fish.

It should be noted that fish in the tropics are often not caught by nets or fishing rods, and with the help of harpoon. Thus, the closer you are to the fish, the easier it is to hook. What do these results indicate? That fish learn to adapt to environmental conditions. In those places where the risk of being caught is relatively low, fish are more careless. On the contrary, their caution increases with distance from protected area, where the risk of being caught increases.

It would seem that the results are not very surprising. Fish behavior is quite plastic and can change depending on surrounding conditions. However, proponents of marine reserves can rejoice in these results that the reserves produce not only larger fish, but the fish easy to catch. That is, if you make the catch on the border of protected areas, it will be much more effective than the traditional catch. Such information can serve as a good advertisement for the creation of new marine reserves.

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