Bluefish, Pomatomus saltatrix gratory pelagic species that occur seasonally in Florida’s inshore a, h rs eters and length-weight relations for bluefish Source 0 0) e a, h rs eters and length-weight relations for bluefish Source 0 0) Bluefish are a schooling, mi and continental shelf waters. In the western Atlantic, bluefish range from Nova Scoti Canada, along the Atlantic coast of the U.S. to Cuba’s northwest coast, throughout the Gulf of Mexico, and along the South American coast from Colombia to Argentina. Tagging and mtDNA analyses show that sufficient mixing occurs between the U.S. gulf and Atlantic coast bluefish populations to maintain a single genetic stock (Miller 1969, Graves et al. 1992a); although, mixing may be limited enough to consider the two groups as separate fishery stocks. Bluefis grow rapidly in their first year of life and achieve a size of 32” fork length (FL) in about 10 yea (Table 1). The maximum age reached by bluefish appears to be about 11 years. Bluefish reach sexual maturity before age 2. Spawning occurs during April and May near the inner reaches of the Gulf Stream off Florida’s Atlantic coast and during April and October–November in the northern Gulf of Mexico. and continental shelf waters. In the western Atlantic, bluefish range from Nova Scoti Canada, along the Atlantic coast of the U.S. to Cuba’s northwest coast, throughout the Gulf of Mexico, and along the South American coast from Colombia to Argentina. Tagging and mtDNA analyses show that sufficient mixing occurs between the U.S. gulf and Atlantic coast bluefish populations to maintain a single genetic stock (Miller 1969, Graves et al. 1992a); although, mixing may be limited enough to consider the two groups as separate fishery stocks. Bluefis grow rapidly in their first year of life and achieve a size of 32” fork length (FL) in about 10 yea (Table 1). The maximum age reached by bluefish appears to be about 11 years. Bluefish reach sexual maturity before age 2. Spawning occurs during April and May near the inner reaches of the Gulf Stream off Florida’s Atlantic coast and during April and October–November in the northern Gulf of Mexico. Table 1. Von Bertalanffy growth param Table 1. Von Bertalanffy growth param Inches FL = L ∞ (1-e -K(age-t 0 ) ) K L ∞ (inches FL) t 0 (years) Inches FL = L Combined (gulf) Combined (gulf) .18 .18 37.2 37.2 -1.033 -1.033 Barger (199 Barger (199 ∞ (1-e -K(age-t 0 ) ) K L ∞ (inches FL) t 0 (years) Combined (Atlantic) 0.096 40.1 -2.493 Barger (1990) inches FL) b a b So 0.00 11 3. FWC-FMR ished data Weight in lbs = a ( urce Combined (Florida) 04 064 I Unpubl opportunistic feeders w d reflects availab prefere 4). ng ed Bluefish are hose foo prey ility and prey nce, especially as it relates to the size of the bluefish (Naughton and Saloman 198 Schools of bluefish can be located at a distance by looking for hovering seagulls that are eati forage fish driven to the surface by feeding bluefish (Olla et al. 1970). Presumably, larvae and juveniles eat zooplankton (Kendall and Walford 1979). The food of young-of-the-year bluefish includes small shrimp, anchovies, killifish, silversides, and crabs (Pottern et al. 1989). In the Gulf of Mexico and off the southeastern U.S., adults prey heavily on schooling fishes such as Atlantic croaker, striped mullet, menhaden, Spanish sardine, Atlantic bumper, and round scad. Invertebrate prey includes portunid crabs, penaeid shrimp, squid, and gastropods. The trophic impacts of bluefish feeding have been investigated for U.S. Atlantic coast waters (Buckel et al. 1999a, 1999b). The estimated prey biomass consumed by bluefish was about eight times the estimated biomass of the bluefish population (Buckel et al. 1999b). Estimated annual consum biomass of butterfish, Peprilus triacanthus; long-finned squid, Loligo pealei; and boreal squid, Illex illecebrosus, was much higher than that harvested by the commercial fisheries for these species during 1982–1994. Bluefish consumption of menhaden, Brevoortia tyrannus, was less ______________________________________________________________________________ Florida Fish and Wildlife Conservation Comm., FWRI (2006) BLUEFISH - 1
Transcript
Bluefish, Pomatomus saltatrix
gratory pelagic species that occur seasonally in Florida’s inshore a,
h rs
eters and length-weight relations for bluefish
Source 0 0)
e a,
h rs
eters and length-weight relations for bluefish
Source 0 0)
Bluefish are a schooling, mi and continental shelf waters. In the western Atlantic, bluefish range from Nova Scoti
Canada, along the Atlantic coast of the U.S. to Cuba’s northwest coast, throughout the Gulf of Mexico, and along the South American coast from Colombia to Argentina. Tagging and mtDNAanalyses show that sufficient mixing occurs between the U.S. gulf and Atlantic coast bluefish populations to maintain a single genetic stock (Miller 1969, Graves et al. 1992a); although, mixing may be limited enough to consider the two groups as separate fishery stocks. Bluefisgrow rapidly in their first year of life and achieve a size of 32” fork length (FL) in about 10 yea(Table 1). The maximum age reached by bluefish appears to be about 11 years. Bluefish reach sexual maturity before age 2. Spawning occurs during April and May near the inner reaches of the Gulf Stream off Florida’s Atlantic coast and during April and October–November in the northern Gulf of Mexico.
and continental shelf waters. In the western Atlantic, bluefish range from Nova ScotiCanada, along the Atlantic coast of the U.S. to Cuba’s northwest coast, throughout the Gulf of Mexico, and along the South American coast from Colombia to Argentina. Tagging and mtDNAanalyses show that sufficient mixing occurs between the U.S. gulf and Atlantic coast bluefish populations to maintain a single genetic stock (Miller 1969, Graves et al. 1992a); although, mixing may be limited enough to consider the two groups as separate fishery stocks. Bluefisgrow rapidly in their first year of life and achieve a size of 32” fork length (FL) in about 10 yea(Table 1). The maximum age reached by bluefish appears to be about 11 years. Bluefish reach sexual maturity before age 2. Spawning occurs during April and May near the inner reaches of the Gulf Stream off Florida’s Atlantic coast and during April and October–November in the northern Gulf of Mexico. Table 1. Von Bertalanffy growth paramTable 1. Von Bertalanffy growth param
Weight in lbs = a ( urce Combined (Florida) 04 064 I Unpubl
opportunistic feeders w d reflects availab
prefere 4). ng
ed
Bluefish are hose foo prey ility and prey nce, especially as it relates to the size of the bluefish (Naughton and Saloman 198
Schools of bluefish can be located at a distance by looking for hovering seagulls that are eatiforage fish driven to the surface by feeding bluefish (Olla et al. 1970). Presumably, larvae and juveniles eat zooplankton (Kendall and Walford 1979). The food of young-of-the-year bluefish includes small shrimp, anchovies, killifish, silversides, and crabs (Pottern et al. 1989). In the Gulf of Mexico and off the southeastern U.S., adults prey heavily on schooling fishes such as Atlantic croaker, striped mullet, menhaden, Spanish sardine, Atlantic bumper, and round scad.Invertebrate prey includes portunid crabs, penaeid shrimp, squid, and gastropods. The trophic impacts of bluefish feeding have been investigated for U.S. Atlantic coast waters (Buckel et al.1999a, 1999b). The estimated prey biomass consumed by bluefish was about eight times the estimated biomass of the bluefish population (Buckel et al. 1999b). Estimated annual consumbiomass of butterfish, Peprilus triacanthus; long-finned squid, Loligo pealei; and boreal squid, Illex illecebrosus, was much higher than that harvested by the commercial fisheries for these species during 1982–1994. Bluefish consumption of menhaden, Brevoortia tyrannus, was less
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than the fisheries landings. In the waters north of Cape Hatteras, predation on bay anchovies, Anchoa mitchilli, was 2.2–6.8 billion fish during the month of September in each of 1994 and 1995 (Buckel et al. 1999a).
Statewide landings of bluefish were 1,200,827 pounds in 2005. These landings were made m
00
rough 1995, commercial catch rates on the Atlantic coast declined, probably reflecti
eld s
rnal abnormalities during 1999-2005 on the Atlanti
recent assessment of the bluefish stock on the U.S. Atlantic coast was based on an ASA
r
d at
lished a fishery management plan fo
1996
into
ostly by recreational fishers (85% of statewide landings by weight) and mostly on theAtlantic coast (77% of statewide total). During 2005, commercial landings of greater than 10,0pounds were reported only from the Atlantic coast’s Brevard County (Fig. 1). Landings made by the recreational fishery were also greatest along the Atlantic coast of Florida during 2005 (Fig. 2). The 2005 total landings were 8% lower than the average landings in the previous five years (2000–2004) and 54% lower than the historical average landings of 1982–2005 (Fig. 3). On the Atlantic coast, total annual landings of bluefish fluctuated during 1982–1993 and declined about2.5 million pounds in 1993 to about 0.85 million pounds in 2001 (Fig. 3). Total annual landings on the gulf coast fluctuated without trend through 1991 then declined to 0.1–0.5 million pounds during 1994–2005.
From 1992 thng the trip limits imposed on the Atlantic coast fishery beginning in July 1993. The
commercial catch rate increased rapidly during 1996-1999 and has held stable at under 20 pounds per trip since 2000 (Fig. 4). On the gulf coast, the commercial catch rate has also hsteady since 2000, at just over 15 pounds per trip (Fig. 5). On the Atlantic coast, total-catch ratefor anglers have steadily increased since 1991 (Fig. 6). Catch rates for anglers in the gulf appear steady at over two fish per trip since 1993 (Fig. 7).
Bluefish did not show alarming rates of extec or gulf coasts, except in about 15% and 2.5% of animals in 2004, respectively (Figs. 8,
9). Ulcer/lesion on the Atlantic coast and fin rot on the gulf coast were the only observed cause of those abnormalities, if any (Figs. 10, 11). Note that the overall numbers of animals collected was rather low.
The mostP model (41st Northeast Regional SAW 2006). It revealed that bluefish stock biomass
declined from a peak level of 176 million lbs in 1982 to 57 million lbs in 1995. Since 1995, thetotal stock biomass increased to 105 million lbs in 2003 (43% higher than the overfished condition defined as 0.5BMSY = 73.5 million lbs according to the current ASMFC-FMP fobluefish). This model indicates that the stock is not experiencing overfishing (41st NortheastRegional SAW 2006). The ASAP model estimated FMSY, FMULT, BMSY and stock biomass in 2004 to equal 0.19, 0.149, 147.05 million lbs and 104.1 million lbs, respectively. FMULT peakeabove 0.4 per year in 1986, 1991 and 1997 and has since declined linearly reaching 0.15 per year in 2004. Average fishing mortality rates for age 1+ bluefish were below the target of 0.41 per year for 2000 through 2004 (41st Northeast Regional SAW 2006).
The Atlantic States Marine Fisheries Commission has estabr bluefish that requires size limits, bag-limits (or conservation equivalencies), and
commercial quotas. Florida, first judged in compliance with these requirements in 1995, established a commercial quota of 877,000 pounds for the Atlantic coast beginning in thecalendar year. Florida’s Atlantic coast commercial landings were only about 134,000 pounds in1996 and 284,000 pounds in 1997, well below the quota allocation. The most recent assessment of bluefish on the Atlantic coast of Florida (De Silva 2002) indicates that the population has shown an increase after the implementation of size- and bag-limit regulations in 1993. The population was relatively stable, at around 4.8 million fish, during 1994-2001. Recruitment
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the fishery was relatively stable; approximately 2.2 million recruits entering the fishery each year, during this period. Fishing mortality rates indicate a steady decline during 1981-1996. During 1996-2001, the annual fishing mortality rate has been stable at approximately 0.16 peryear. On the gulf, the most recent assessment (Heinemann 2002) concluded that biomass levelswere between 0.12 and 0.26 of the B
MSY, and that overfishing continues to occur.
Figure 1. Geographic distribution of commercial landings of bluefish during 2005
Figure 2. Geographic distribution of recreational landings of bluefish during 2005
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Com-Atlantic Rec-Atlantic Com-Gulf Rec-Gulf
Figure 3. Total landings of bluefish on the Atlantic and gulf coasts of Florida, 1982–2005
Figure 4. Annual standardized commercial catch rates (pounds) for bluefish on the Atlantic coast of Florida, 1992–2005
Figure 5. Annual standardized commercial catch rates (pounds) for bluefish on the gulf coast of Florida, 1992–2005
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Figure 6. Annual standardized recreational total-catch rates (numbers) for bluefish on the Atlantic coast of Florida, 1991–2005
Figure 7. Annual standardized recreational total-catch rates (numbers) for bluefish on the gulf coast of Florida, 1991–2005
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Figure 8. Proportion of bluefish ≥75 mm long collected in fisheries-independent-monitoring sets on the Atlantic coast that had gross external abnormalities, 1999-2005
Figure 9. Proportion of bluefish ≥75 mm long collected in fishery-independent-monitoring sets on the Atlantic coast that had gross external abnormalities, 1999-2005
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Figure 10. Proportions of different gross external abnormalities in bluefish ≥75 mm long collected in fishery-independent-monitoring sets on the Atlantic coast, 1999-2005
Figure 11. Proportions of different gross external abnormalities in bluefish ≥75 mm long collected in fishery-independent-monitoring sets on the gulf coast, 1999-2005
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