Animals and places affected
The most vulnerable places in the world where bycatch is widely practiced and seriously affects the population include the Arctic, coastal East Africa, Coral Triangle, the Gulf of California, Mesoamerican Reef, Southern Chile, the Galapagos, etc. Animals that are mostly impacted by bycatch are the vaquita, the whale shark, the blue whale, the gray whale, the great white shark, the green turtle, Hector’s dolphin, the leatherback turtle, sea lions, penguins, albatrosses, etc.
The highest rate of bycatch of non-targeted species that was recorded was the trawling of tropical shrimp. Generally, trawl nets and shrimp trawls, particularly, have been recognized as sources of mortality for cetaceans and finfish species. In 1997, FAO found that discard rates of shrimp were as high as 20:1 with a world average of 5,7:1. “Alverson et al, for instance, suggest, that in the Northwest Pacific 97% of the shrimp bycatch is discarded producing over 4 million tonnes of waste fish. This, however, is countered by information provided by Zhou and Yimin (1996) who suggest that the Chinese shrimp trawl fleet discards very little of the non-shrimp catch. According to Zhou and Yimin, the shrimp fishery of China catches about 1.8 million tonnes of bycatch all of which is used, much for feeds for the Chinese aquaculture industry. In Southeast Asia, there has also been a growth in recent years in industry’s which use bycatch from shrimp fisheries for human consumption.
Recent (1997) evidence from the countries of Central America and the Caribbean suggest that the amount of incidental catch that is now utilized in the region is greater than that suggested by Alverson et al. In countries such as Belize, Colombia, Costa Rica, and Nicaragua, for instance, it seems that between 20 and 30% of the once discarded bycatch is now utilized, and in Venezuela, it is probably at least 30%. In Guyana and Brazil, the amount of utilization has increased and probably now accounts for about 10% of the incidental bycatch. In Cuba, where the state operates fishing, marketing, processing, and distribution, it is thought that virtually all edible bycatch is now used which probably accounts for up to 70% of the non-shrimp catch.”
Read more: FAO: A Study of the Options for Utilization of Bycatch and Discards from Marine Capture Fisheries
Cetaceans are also affected by bycatch. It is commonly known that many cetaceans are caught for further sale to entertainment parks, food in some countries, or scientific purposes, however, these animals are victims of bycatch too. For instance, dolphins, turtles, and whales suffer from bycatch through direct capture by hooks, trawl nets, fishing gears. At present, the number of cetacean bycatch is increasing in intensity and frequency. One of the most common examples of cetacean bycatch is dolphins that are caught in tuna nets. Because dolphins are mammals, they die drowning stuck in nets under the water. Also, the Caspian seal bycatch is recognized as one of the biggest entanglements of pinnipeds across the globe.
Read more: Assessment of the Sturgeon Catches and Seal Bycatches in an IUU Fishery in the Caspian Sea
If underwater bycatch might be common, unfortunately, seabirds are also affected by this practice. The IUCN Red List has 21 species, while 19 of them are listed as Threatened, and the other two are classified as Near Threatened. One of the major threats for albatrosses is commercial long-line fishing because these and other seabirds who feed on offal are attracted to the set bait, after which they get hooked on the lines and it makes them drown and die.
Read more: Albatross Mortality and Associated Bait Loss in the Japanese Longline Fishery in the Southern Ocean