Heavy fishing at spawning areas also further depletes males. Overfishing has snared many females that might potentially turn into males and has thrown the natural process out of balance. Gag are protogynous hermaphrodites, meaning all start as female and some develop into males at 11 years old or about 43 inches. Male gags have dropped from as high as 17 percent of the population in the 1970s to as low as 2 percent since the 1990s, leaving fewer breeders.
In the past, only a small portion of spawning habitat was protected and a lack of scientifically sound fishing limits contributed to the species' decline. The fish have been caught at more than 2.5 times the sustainable rate. The fish have been caught at more than 2.5 percent of a minimum healthy level. The gag grouper population has been sliced nearly in half since 2004 and is at about 40 percent of a minimum healthy level. Maintains 22-inch recreational minimum size limit keeps daily limit of two gag and four total grouper.Commercial size limit reduced from 24 to 22 inches.Annual changes in quotas and other rule adjustments, such as length of the fishing season, may be necessary to maintain catch at prescribed levels.Increases in catch limits contingent upon staying with prescribed quotas.Annual targeted recreational catch for 2012, 1.031 million pounds 2013, 1.287 million pounds 2014, 1.519 million pounds 2015, 1.708 million pounds.Recreational fishing open July 1 through Oct.* Enacted pending approval of long-term plan Recreational target of 620,000 pounds.Commercial quota at 430,000 pounds to allow for accidental catch.Quota program limits the number of commercial fishermen and caps the amount each can keep.All grouper species limited to four fish per person per fishing trip.Recreational fishing season closed February and March.Size limit: 24 inches, commercial 22 inches, recreational.Two gag per person per recreational fishing trip.Annual catch allowed: commercial, 1.49 million pounds recreational, 2.14 million pounds.In further decline after 1 in 5 gag died in 2005 in the wake of a major red tide.Frequently caught and killed by accident when fishermen target other species.Easily caught and found in well-known spawning grounds.Predominantly female they outnumber males 30 to 1, leaving fewer breeders.Fished at more than 2.5 times the sustainable rate.At about 40 percent of a minimum healthy population level.But those rules could be relaxed as gag grouper show signs of recovery. It calls for a shorter recreational fishing season, reduced commercial catch, and other protections. A recovery plan can help this species rebound. But since 2004, the population has been sliced nearly in half. While our model suggests that the reserves currently in place should result in a small increase in adult sex ratio given the current level of fishing mortality, such benefits might not be achieved in practice given possible future changes in transition rates or fisher behavior.If you think of a mouthwatering fish sandwich, it may be gag grouper.
When we included density-dependent sex change in the model, the results showed a reduction in the sex ratio under high fishing pressure when compared to model simulations when sex change was fixed. Fisher response to reserves also had a large impact on reserve success. In general, larger reserves resulted in higher adult populations and sex ratio. We modeled the GOM gag grouper population under a range of potential reserve sizes and fisher responses.
Reserve success is ultimately a function of the total amount of spawning aggregations protected, and fisher response to reserve implementation may have significant influence on the ultimate effectiveness of the reserves. In the Gulf of Mexico (GOM), two marine reserves were put in place in order to protect spawning aggregations of gag grouper, which has experienced a steep decline in the male to female sex ratio since the 1970s. The use of marine reserves for fishery management remains a controversial tool despite evidence of their success.
0 kommentar(er)
