Grunts, Family Haemulidae Tomtate, Haemulon aurolineatum Cuvier, 1830

Pigfish, Orthopristis chrysoptera (Linnaeus, 1766)

White grunt, Haemulon plumierii (Lacepède, 1801) 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 plumierii, or to a lesser extent tomtate, H. aurolineatum. Numerous grunt species with more tropical affinities are also caught in Florida waters including black margate, Anisotremus surinamensis; porkfish, A. virginicus; margate, H. 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). Table 1. Von Bertalanffy growth parameters and length-weight relations for white grunt Inches TL = L ∞ (1-e-K(age-t0)) Combined sexes, Carolinas Combined sexes, Florida Atlantic coast Males, Florida gulf coast, north-central Females, Florida gulf coast, northcentral Males, Florida gulf coast, central Females, Florida gulf coast, central

K

L ∞ (inches TL)

t 0 (years)

0.11 0.19 0.41 0.35

25.2 12.9 13.6 12.5

Source

-4.21 -0.85 -1.68

Manooch (1976) Potts and Manooch (2001) Murie and Parkin (2005) Murie and Parkin (2005)

0.36 0.30

12.6 11.6

-1.89 -3.44

Murie and Parkin (2005) Murie and Parkin (2005)

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Table 1. (continued) Von Bertalanffy growth parameters and length-weight relations for white grunt Weight in lbs = a (inches TL)b Combined sexes, Carolinas Combined sexes, Florida gulf coast Combined sexes Florida Atlantic coast

a

b

0.000534 0.000930 0.000950

3.02 2.75 2.73

Source Manooch (1976) Murie and Parkin (2005) Potts and Manooch (2001)

Table 2. Length-weight relation for pigfish Weight in lbs = a (inches FL)b Sex combined, southern Florida

a

b

0.000347

2.99

Source Bohnsack and Harper (1988)

There is little published information on white grunt and pigfish food and feeding habits. Juvenile white grunt and pigfish may feed primarily on benthic crustaceans, worms, and mollusks, while adults may feed on shrimp, crabs, and mollusks (Sierra et al.1994; Darcy 1983a). Predators of pigfish included spotted seatrout, sand seatrout, and sharks and rays (Darcy 1983b). Randall (1967) reported dog snappers as one of the major predators feeding on white grunts. Total landings of grunt in Florida during 2013 were 2,795,631 pounds, 78% of which were made by recreational anglers. Landings were greater on the gulf coast, where about 87% of the statewide landings were made in 2013. Commercial landings of grunts were reported along the majority of the Atlantic coast, with the highest landings in Brevard County (Fig. 1a). On the gulf coast, commercial landings were greatest in Pinellas, Dixie, and Wakulla Counties (Fig. 1a). Recreational landings of grunts were high across all coastal regions of Florida (Fig. 1b). Total annual landings of grunt are much lower on the Atlantic Coast than on the Gulf Coast, and have fluctuated without much of a trend since 1982 (Fig.2). On the gulf coast, total landings approximately doubled to over 3 million pounds from the mid-1980s through 1995, declined somewhat through the late 1990s, increased through 2001, have fallen to under 1 million pounds in 2006-2007 and increased again through 2013 (Fig. 2). The 2013 total landings were 43% higher than the average landings in the previous five years (2008–2012) and were 16% higher than the historical average landings (1982–2012). Commercial landings rates have fluctuated on the Atlantic coast with no apparent longterm trend until 2001, after which landings rates have declined steadily (Figs. 3a). On the gulf coast, commercial landings rates were relatively stable until 1997, but they exhibit a linear increase from 1996 to 2000 before declining in 2001 and 2002, since 2002 catch rates again exhibit a linear increase through 2005, declined again in 2006 (Fig. 3b) and are showing another general linear increase from 2007-2013. Grunt species were pooled in the analyses of total landings and commercial landings 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.

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Juvenile pigfish are highly sought after as a bait species. The recreational total catch rates for pigfish have remained fairly stable on the Atlantic coast since 1991 (Fig. 3c). Pigfish total catch rates were stable with little variation on the gulf coast from 1995-2002, after which catch rates have declined through 2007 and increased through 2011 (Fig 3d). Atlantic coast angler total catch rates for white grunt are variable, but show a general decreasing trend from 1991-2009, followed by an increase through 2013 (Fig. 3e). On the gulf coast, white grunt total catch rates were fairly stable through 2004, since then rates have declined through 2006 and trending upward from 2007-2012 (Fig. 3f). Indices of YOY pigfish abundance on the Atlantic coast show cyclic fluctuations increasing trends followed by drops in abundance in 2004, 2007, and 2013. (Fig. 4a). On the gulf coast there was a notable high in 1998 after which there has been a downward trend through 2006, followed by increasing abundances similar to historical levels in 2008-2013 (Fig. 4b). Post-YOY abundances of pigfish on the Atlantic coast have v-shaped abundance trends with lows in 2000, 2006, 2012-2013 and peaks in 2003 and 2011 (Fig. 4c). On the gulf coast abundances were variable following low levels in 1997, declined sharply in 2005- 2006, and then showed a steep upward trend through 2012 (Fig. 4d). Occurrence of gross external abnormalities in pigfish on the Atlantic coast was highest in 2011, while they varied without trend on the gulf coast with a peak in 2010 (Figs.5a and 5b). Skeletal abnormalities, parasites, and fin rot were common among affected pigfish along the Gulf coast (Figs. 5c and 5d). 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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a. Commercial landings (pounds)

b. Recreational landings (numbers)

Figure 1 (a)-(b). Geographic distribution of grunts landed during 2013. (a) Commercial landings (pounds) by county; (b) Recreational landings (numbers of fish) by region.

Figure 2. Total annual landings (pounds) of grunts on the Atlantic and gulf coasts of Florida, 1982–2013.

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a.

Atlantic, commercial landings rates (pounds/trip), grunts

b. Gulf, commercial landings rates (pounds/trip), grunts

c. Atlantic, recreational landings rates (numbers/trip), pigfish

d. Gulf, recreational landings rates (numbers/trip), pigfish

e. Atlantic, recreational landings rates (numbers/trip), white grunt

f. Gulf, recreational landings rates (numbers/trip), white grunt

Figure 3 (a)-(f). Annual standardized landings rates for grunts in Florida. Commercial landings (pounds/trip) 1992-2013: (a) Atlantic Coast grunts; (b) Gulf Coast grunts. Recreational total catch rates (numbers/trip) 1991-2013: (c) Atlantic Coast pigfish; (d) Gulf Coast pigfish; (e) Atlantic Coast white grunt; (f) Gulf Coast, white grunt. ___________________________________________________________________________ Florida Fish and Wildlife Conservation Commission, FWRI (2014) GRUNTS - 92

a. Atlantic coast YOY

b. Gulf coast YOY

c. Atlantic coast post-YOY

d. Gulf coast post-YOY

Figure 4(a)-(d). Proportion of fishery-independent-monitoring sets that captured pigfish from 1997-2013. Young-of-the-year (YOY): (a) Atlantic coast; (b) Gulf coast. Post-YOY: (c) Atlantic Coast; (d) Gulf coast.

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a. Atlantic coast proportion to total collected

b. Gulf coast proportion to total collected

c. Atlantic coast percentage of abnormality types

d. Gulf coast percentage of abnormality types

Figure 5(a)-(d). Gross external abnormalities of pigfish ≥ 75mm collected in fishery-independent-monitoring sets, 1999-2013. Breakdown of gross external abnormalities by coast: (a) Atlantic coast; (b) Gulf coast. Percentage of abnormalities by type: (c) Atlantic Coast; (d) Gulf coast

Florida Fish and Wildl. Conserv. Comm., FWRI (2014)

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