Marine protected areas help West Coast rockfish population rebound

SOUTHERN CALIFORNIA — A fish species once in danger of collapsing is now swimming off the Southern California coast in large numbers.

A study published in Royal Society Open Science declared the West Coast rockfish has rebounded after being severely overfished at the turn of the century.

The finding was part of a larger report on the role marine protected areas, or MPAs, play in facilitating the recovery of diminished fish stocks.

“Marine protected areas (MPAs) can facilitate recovery of diminished stocks by protecting reproductive adults. To effectively augment fisheries, however, reproductive output must increase within the bounds of MPAs so that larvae can be exported to surrounding areas and seed the region,” researchers associated with the study stated.

Scientist from National Oceanic and Atmospheric Administration (NOAA), University of San Diego and University of Massachusetts Amherst conducted the study.

“Protecting important ocean habitat promotes the long-term recovery of rockfish such as cowcod and bocaccio that have long been a staple of West Coast fishermen. Favorable ocean conditions also played a role,” a NOAA statement said. “West Coast rockfish species in deep collapse only 20 years ago have multiplied rapidly in large marine protected areas off Southern California, likely seeding surrounding waters with enough offspring to offer promise of renewed fishing.”

Establishing MPAs provide “ecological refuges” to defend various fish species from the negative effects of overfishing, according to the study’s scientists.

There is still much work to be done, however, to truly understand the benefits of an MPA, according to study.

“One difficulty in evaluating MPA effects has been a lack of robust sampling designs. MPA impacts may be masked or misinterpreted if, for example, samples are collected only within MPA bounds without outside control locations,” scientists stated in their report. “Furthermore, inside and outside locations should be paired such that habitat conditions are similar inside and outside of MPAs.

“An ideal set-up will monitor both before and after MPA establishment to determine if sample (e.g. fish abundances) trajectories diverge inside and outside following placement of MPAs,” scientists continued in their report.

Scientists ultimately stated their study “provides an example of how larval monitoring can be used to assess MPA efficacy.”

The study reviewed trends of eight historically fished species and seven non-fished species between 1998 and 2013.

“Scientists found that larvae of most of the rockfish species historically targeted by fishing increased throughout Southern California waters, but especially within the protected conservation areas,” NOAA said in its statement of the study. “Species that were not historically fished increased at about the same rate both inside and outside the protected areas, indicating that rockfish spawning was high within the protected areas.”


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