1999 



OUR LIVING OCEANS 



Shrimp boat, Corpus Christ!, 

 Texas. 



that level in recent years. White and pink shrimp 

 have not shown any general trend, aithotigh pink 

 shrimp stocks have rebounded from the low val- 

 ues experienced in the early 1990's. The brown 

 shrimp increase appears related to marsh alter- 

 ations. Coastal sinking and a sea-level rise in the 

 northwestern Gulf iiuuidatcs intertidal marshes 

 longer, allowing the shrmip to feed for longer pe- 

 riods within the marsh area. In the Gulf, both fac- 

 tors have also expanded estuarine areas, created 

 more marsh edges, and provided more protection 

 from predators. As a result, the nursery function 

 of those marshes has been greatly magnified and 

 brown shrimp production h,is expanded. However, 

 continued subsidence will lead to marsh deterio- 

 ration and an ultimate loss of supporting wetlands, 

 and current high fishery yields may not be indefi- 

 nitely sustainable. Parent stock indices for the three 

 major Gulf species are shown in Figure 11-1. 



Spiny Lobster 



Annual Florida spiny lobster landings were 

 fairly stable during the 1980s, running about 

 2,700 metric tons (t) from the tiult of Mexico 

 (Figure 11-2), but yielding recent high landings 

 in 1994 of 3,222 t, with ex-vessel revenue of about 

 530,000,000. On Florida's Atlantic Coast, land- 

 ings have averaged 230 t, valued at $2,000,000. 

 The fishery is considered overcapitalized with ap- 

 proximately 900,000 lobster traps fished during 

 1992. In 1993, a trap reduction program was es- 

 tablished, not to exceed 1 0"/\} per year, which would 

 maintain or maximize sustainable spinv lobster 

 harvest from the fishery. Excessive effort in the 

 fishery has been estimated to occur when the num- 

 ber of traps fished exceeds 300,000/year. Spiny 

 lobster fishermen use live undersized lobsters as 

 attractants in their traps, but due to a high mor- 

 tality rate for these "live bait " animals, about 30- 

 50% of the potential yield is lost. The recreational 

 fishery in Florida had over 120,000 participants 

 purchasing recreational lobster stamps during the 

 1991 season. Recreational spiny lobster catches 

 were estimated to comprise 41% of total landings 

 during the first month and 22"ci of the total 1991- 

 92 season landings. 



Annual spiny lobster landings for Puerto Rico 

 have averaged 1 26 t over the past 27 years, vary- 



ing from 103 tin 1972 to a high of 223 tin 1979. 

 No precise data are available on fishing effort, but 

 the Puerto Rican stock produced landings of 72 t 

 in 1992 and now appears to be overutilized. U.S. 

 Virgin Islands landings for 1980-88 were fairlv 

 stable, averaging 19 t. 



Spiny lobster larvae may drift at sea for 9 

 months, and thus identification of their source or 

 parent stock is almost impossible. There is a prac- 

 tical management need to know far more about 

 their origin and subsequent movement into the 

 fishery. 



Stone Crab 



Annual catches of stone crab (claw weight) 

 varied from 1 ,200 to 1 ,400 t on the Gulf of Mexico 

 and Atlantic coasts through the 1980s, with a 

 record 3,065 t landed during 1994 (Figure 1 1-2). 

 Recent annual ex-vessel revenue averaged $18 

 million. The number of stone crab traps fished 

 seasonally increased from 295,000 in 1979-80 to 

 567,00 in 1984-85 to a record 745,000 during 

 1992-93. While total landings have increased 

 modestly in recent vears, it is clear that these land- 

 ings are the result of increased fishing effort (num- 

 ber of traps fished), especially during the early 

 months of the stone crab season. 



ISSUES 



Habitat Concerns 



I'lstuarine and marsh loss remove critical habi- 

 tat for young shrimp. Additional studies are needed 

 to further assess the impacts of human-induced 

 changes in habitat availability, environmental con- 

 ditions, predator abundance, and pollution in the 

 nurserv areas. Florida spinv lobsters depend on reef 

 habitat and shallow-water algal flats for feeding 

 and reproduction. Fhese habitat requirements may 

 conflict with expanding coastal de\elopments. The 

 productivity of stone crabs in Florida Bay is re- 

 lated to water quality' and flow through the Ever- 

 glades. Specific water requirements need to be 

 identified and maintained through comprehensive 

 Everglades water management. A unified program 

 to integrate and study the effects of environmen- 

 tal alterations, fishing technology, regulations, and 



1 46 



