Pigfish, Orthopristis chrysoptera
White grunt, Haemulon plumieri.
Several different species of grunt are caught in Florida waters. Inshore fishers typically
encounter pigfish, Orthopristis chrysoptera, while offshore fishers are more likely to encounter
white grunt, Haemulon plumieri, or to a lesser extent tomtate, Haemulon aurolineatum.
Numerous grunt species with more tropical affinities are also caught in Florida waters including
black margate, Anisotremus surinamensis; porkfish, A. virginicus; margate, Haemulon album;
French grunt, H. flavolineatum; cottonwick, H. melanurum; sailors choice, H. parra; and striped
grunt, H. striatum. Darcy (1983a, 1983b) summarized life histories of pigfish, white grunt, and
tomtate. Most grunt are small- to medium-sized fishes that occur in areas of moderate relief or
with seagrass beds. White grunt reach about 21" total length (TL) and 9–12 years old (Table 1);
pigfish reach 18" standard length (SL) and 3–4 years old (Table 2). White grunt mature at age 3
or 10.6" fork length (FL), and pigfish mature at age 2 or 7.4" FL. Peak spawning activity for
white grunt and pigfish occurs during spring; although, some year-round spawning may occur in
offshore areas. Growth is rapid until maturity is reached. Findings from a study of white grunt
life history in the eastern Gulf of Mexico indicate that white grunt get as old as 18 years (Murie
and Parkyn 2005). Growth is rapid through ages 4 or 5 then reaches a plateau at about 275–325
mm total length (TL) and showed sex-specific and regional differences. An estimate of total
annual mortality from catch curves was 0.30 for white grunt sampled from the headboat fishery
catch in the eastern Gulf of Mexico during 1998 (Murie and Parkyn 2002).
Total landings of grunt in Florida during 2005 were 2,297,043 pounds, 83% of which
were made by recreational anglers. Landings were greater on the gulf coast, where about 86% of
the statewide landings were made in 2005. Commercial landings of grunts occurred primarily in
Palm Beach and Dade Counties on the Atlantic coast (Fig. 1). On the gulf coast, commercial
landings were greatest in Dixie and Pinellas Counties (Fig. 1). Recreational landings of grunts
were high across all coastal counties of Florida (Fig. 2).
Total annual landings of grunt have fluctuated without any significant trends since at
least 1982 on the Atlantic coast (Fig.3). On the gulf coast, total landings increased from 1982
through the mid-1990s, declined slightly during 1996–1998, but they increased to near the 1994
and 1995 levels in 2001, and have declined steadily since (Fig. 3). The 2005 total landings were
25% lower than the average landings in the previous five years (2000–2004) and were 11%
lower than the historical average landings (1982–2005).
Commercial catch rates have fluctuated on the Atlantic coast with no apparent long-term
trend until 2001, after which catch rates have declined steadily (Figs. 5). On the gulf coast,
commercial catch rate were relatively stable until 1997, but they exhibit a linear increase in catch
rate from 1996 to 2000 before declining in 2001 and 2002, since 2002 catch rates again exhibit a
linear increase through 2005 (Fig. 5).
Grunt species were pooled in the analyses of total landings and commercial catch rates
because this was the lowest level of identification available in the Marine Resources Information
System database. Species-specific information is available in the Marine Recreational Fishery
Statistics Survey database. These data indicate that white grunt and pigfish compose a substantial
part of the recreational landings of grunts: 41% on the Atlantic and 89% on the gulf coasts by
weight in 1995. On both coasts, the annual recreational harvest of white grunt is almost always
more than that for pigfish.
Juvenile pigfish are highly sought after as a bait species. Total-catch rates for pigfish
have remained fairly stable on the Atlantic coast since 1991 (Fig. 6). Pigfish catch rates were
stable with little variation on the gulf coast through 2002, after which catch rates have declined
through 2005 (Fig 7). Atlantic coast angler total-catch rates for white grunt are quite variable
with no apparent trend in the data through 2001, after which catch rates have stabilized (Fig. 8).
On the gulf coast, white grunt total-catch rates were fairly stable through 2002, since then catch
rates have declined through 2005 (Fig. 9).
Indices of YOY pigfish abundance fluctuated with a slight increasing trend through 2003,
but weak year classes in 2004 and 2005 on the Atlantic coast, while on the gulf coast there was a
notable high in 1998 and weak year classes in 1996, 2002, and 2005; otherwise there was little
trend on the gulf coast (Figs. 10, 11). Post-YOY abundances of pigfish on the Atlantic coast
were without trend through 2003, since then abundances have decreased, while the gulf coast
abundances were variable following low levels in 1996–1997, and then declined sharply in 2005,
possibly due to red tide (Figs. 12, 13). Occurrence of gross external abnormalities in pigfish on
the Atlantic coast was highest in 2000 and 2001 and varied without trend on the gulf coast
following with the highest level in 2004 (Figs. 14, 15). Skeletal abnormalities were common
among affected pigfish along both coasts; although non-classified (other) abnormalities were
most common on the Atlantic coast while ulcers/lesions and parasites were most common on the
gulf coast (Figs. 16, 17).
Estimates of white grunt biomass indices showed a flat to slight downward trend on both
coasts of Florida (Murphy et al. 1999). During 1994-1998, recruitment of white grunt varied
without trend on the Atlantic coast; recruitment has varied without trend on the gulf coast during
1987-1998. The 1999 stock assessment indicated that white grunt populations in Florida were
likely to be able to sustain their current levels of fishing mortality rates (0.47–0.49 per year on
the Atlantic coast and 0.25–0.28 per year on the gulf coast; Murphy et al. 1999). Estimated
spawning potential ratios ranged from 32% to 35% on the Atlantic coast and from 43% to46% on
the gulf coast. Based on growth and age information collected in South Florida (Potts and
Manooch 2001), Potts (2000) used an uncalibrated separable virtual population analysis to
estimate population size in numbers-at-age by year. Age at entry for southeast Florida was 1 year
and age at full recruitment was 3 years. With natural mortality (M) set equal to 0.3 per year,
fishing mortality on fully recruited ages was 0.33 per year for southeast Florida. Based on M =
0.3, yield per recruit was 0.24 pounds, and the spawning potential ratio (SPR) for white grunt in
southeast Florida was estimated at 61% (Potts, 2000). Potts (2000) also noted that the 1998
fishing mortality rate could be increased by a factor of three to increase the yield per recruit by
40% while maintaining the stock above 40% SPR. Finally, de Silva and Murphy (2001) noted
the difficulties in estimating commercial catch of white grunt when assumptions were required
about the species composition within the inclusive ‘grunt’ categories.
No formal stock assessment for pigfish is available at this time.
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Florida’s Inshore and Nearshore Species
by Florida Fish and Wildlife Research Institute
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