This is the conclusion reached by a team led by philipp neubauer of rutgers university (new jersey), which used various data sets in its model calculations. The majority of the 153 fish species and invertebrates studied can tolerate moderate overfishing and can recover within ten years if the stock in question has not yet completely collapsed and the pressure from fishing is quickly and significantly reduced.
For many overfished stocks, however, protective measures have come too late, and the ongoing fishery has caused them to collapse, neubauer and colleagues write in the journal science. If already severely depleted stands continue to be overfished, recovery is doubtful.
One example is the north sea cod, said rainer froese of geomar, the helmholtz center for ocean research in kiel, germany. Year after year the european ministers of agriculture allowed far excessive catches, even though the stock was outside safe biological limits. From the southern north sea, i.E. The german waters, the cod has meanwhile been very strongly reduced. Nevertheless, fishing was allowed to continue this year, with about three times the sustainable high mab.
"It seems as if the fish have generally been able to recover well within ten years," neubauer said in an interview with the news agency dpa. "That surprised us a bit."According to neubauer, the results could also be an indication that moderately overfished species adapt to hunting by humans and, for example, produce offspring earlier and more frequently than fish species that are rarely on the dinner plate.
The longer and more heavily humans overfished a species, the more difficult it became to predict its future development and chances of recovery, according to the study. "The lower you drive the biomass of a stock, the less you can predict how that stock will develop in the future," neubauer said.
According to the FAO, nearly 30 percent of the world’s fish stocks were overexploited in 2012, and 57 percent were at the limit of maximum exploitation. However, the situation in the completely overfished areas has improved slightly.
The european union plans a historic reform to better protect stressed fish stocks in the future – but it is not yet in force. In the future, fishermen should only catch as many fish as they can regrow. With more targeted fishing techniques, they should also prevent unintentional bycatch. In addition, a ban on discarding dead fish is to be introduced in order to better control the development of fish stocks. If fishing pressure was immediately reduced well below the sustainable high mab, fishermen could catch more in as little as three to four years than they do today, according to geomar studies, froese said.