(DRAFT) - Taxonomy
                               Species menhaden, gulf
                                 Species Id M010026
                                   Date 26 AUG 96



TAXONOMY

NAME - menhaden, gulf OTHER COMMON NAMES - pogy, sardine and large-scale menhaden ELEMENT CODE - CATEGORY - Fish PHYLUM AND SUBPHYLUM - , CLASS AND SUBCLASS - Osteichthyes, ORDER AND SUBORDER - Clupeiformes, FAMILY AND SUBFAMILY - Clupeidae, GENUS AND SUBGENUS - Brevoortia, SPECIES AND SSP - patronus, SCIENTIFIC NAME - Brevoortia patronus AUTHORITY - Goode TAXONOMY REFERENCES - 126 COMMENTS ON TAXONOMY - Other common names....Pogy, sardine, large-scale menhaden.*126* Taxonomy - 1
                                  (DRAFT) - Status
                               Species menhaden, gulf
                                 Species Id M010026
                                   Date 26 AUG 96



STATUS

Coded Status Commercial Existing, FMP exists Commercial/consumption Commercial/industrial Commercial/bait REFERENCES FOR STATUS - 126 and 192 COMMENTS ON STATUS - Gulf menhaden support the largest single fishery (by weight) in the United States, and their young are prey to many other species of sport or commercial importance.*126* The gulf menhaden fishery is conducted within the territorial sea and offshore of five coastal states (Florida to Texas). All states voted in favor of a cooperative management plan under the Gulf States Marine Fisheries Commission in 1977. This plan was revised and adopted in 1983.*192* Status - 1
                               (DRAFT) - Distribution
                               Species menhaden, gulf
                                 Species Id M010026
                                   Date 26 AUG 96



DISTRIBUTION

Distribution - 1
     

HABITAT ASSOCIATIONS

NATIONAL WETLAND INVENTORY CODES NWI NWICLS NWIMOD NWISPEC Marine OW0 Marine OW0 1 Marine OW0 Marine OW0 1 Marine OW0 Estuarine OW0 Estuarine OW0 Marine OW0 Lacustrine, littoral OW0 8 Marine OW0 Estuarine OW0 9 REFERENCES FOR NWI - 126 Habitat Associations - 1
                                (DRAFT) - Food Habits
                               Species menhaden, gulf
                                 Species Id M010026
                                   Date 26 AUG 96



FOOD HABITS

TROPHIC LEVEL - FILTERER OMNIVORE REFERENCES FOR TROPHIC LEVEL - 126 LIFESTAGE FOOD FOOD PART General Zooplankton Not Applicable Larva See Comments; Food Juvenile Detritus - Organic Not Applicable Juvenile See Comments; Food Adult Detritus - Organic Not Applicable Adult See Comments; Food REFERENCES FOR GENERAL FOOD - 126 REFERENCES FOR ADULT FOOD - 126 REFERENCES FOR JUVENILE FOOD - 126 REFERENCES FOR LARVAE FOOD - 126 COMMENTS ON FOOD - Gulf menhaden have two distinct feeding stages in their lifetime. Up to 30 to 33 mm TL, larvae have a slender body, large mouth and eyes, and relatively short gill rakers, and feed as selective carnivores on individual zooplankters. After transformation into juveniles and as adults, the body is deeper, gill rakers "elongate and branch to form a basket-like seive," and they feed as omnivorous filterers of phytoplankton, zooplankton, and organic detritus. Gunter (1938) reported "large schools feeding near the surface in Caminada Bay, Louisiana where they wheeled, turned and swerved from side to side in perfect unison, all the while with mouths agape and lower jaws thrust forward."*126* COMMENTS ON ADULT FOOD - After transformation into juveniles and as adults, the body is deeper, gill rakers "elongate and branch to form a basket-like seive," and they feed as omnivorous filterers of phytoplankton, zooplankton, and organic detritus.*126* COMMENTS ON JUVENILE FOOD - (Please see C.FOOD.A) COMMENTS ON LARVAE FOOD - Up to 30 to 33 mm TL, larvae have a slender body, large mouth and eyes, and relatively short gill rakers, and feed as selective carnivores on individual zooplankters.*126* Food Habits - 1
                         (DRAFT) - Environment Associations
                               Species menhaden, gulf
                                 Species Id M010026
                                   Date 26 AUG 96



ENVIRONMENTAL ASSOCIATIONS

G = General A = Adult LIM = Limiting RA = Resting Adult J = Juvenile FA = Feeding Adult RJ = Resting Juvenile BA = Breeding Adult FJ = Feeding Juvenile P = Pupae L = Larvae E = Egg RL = Resting Larvae FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS G Water Temperature: Specified in Comments G LIM Dissolved Oxygen: Specified in Comments G Turbidity: Unknown G Relation to Substrate: Unattached - normally free living G Bottom Type [Aquatic]: Mud or silt G Bottom Type [Aquatic]: Organic debris G Water Depth Preference: Specified in Comments G Estuarine habitat zone: bay REFERENCES FOR ENVIRONMENTAL ASSOC_ - 126 REFERENCES FOR LIMITING ENVIRONMENTAL ASSOC_ - 126 COMMENTS ON ENVIRONMENTAL ASSOCIATIONS - Temperature: Gulf menhaden have been taken in water from 5 degrees to 34.9 degrees C (41 degrees to 95 degrees F). Definitive data on thermal optima within this range, upper, and particularly on lower lethal limits are lacking. Avoidance of water temperatures above 30 degrees C (86 degrees F) has been reported. Gunter and Christmas (1960) reported that fisheries activities for Gulf menhaden in Mississippi Sound began in the spring as water temperatures reached 23 degrees C (73 degrees F) and slowed in the fall at approximatley this same temperature.*126* Salinity: While Gulf menhaden have been reported to occur in waters from fresh to hypersaline (0 to 67 ppt), there may be somewhat narrower salinity ranges with which various life stages are associated. Generally, gravid adults, fertilized eggs, and early larvae were associated with the higher salinity gulf and open bay waters. Postlarvae and juveniles appeared to tolerate a wide range, but were most often associated with nearshore, low salinity areas. Non-gravid or developing adults were associated with mid-range salinities of the estuary. Tagatz and Wilkens (1973) reported that juveniles entered freshwater, but never penetrated far (1.6 km or 1 mi) beyond the interface with low salinity estuarine water. Simmons (1957) reported that juveniles commonly occurred in waters from 20 to 60 ppt, but also noted mass mortalities of Gulf menhaden at salinities over 80 ppt.*126* Environment Associations - 1 (DRAFT) - Environment Associations Species menhaden, gulf Species Id M010026 Date 26 AUG 96 Temperature and Salinity: Perhaps the most complete compilation of combined temperature and salinity data for Gulf menhadens is that of Christmas and Waller (1973) for Mississippi Sound. While their matrix covered a wide range of temperatures and salinities within those discussed above, it was apparent that consistently high catches were resticted to waters over 20 degrees C (68 degrees F), particularly 25 degrees to 34.9 degrees C (77 degrees to 95 degrees F), between salinities of 5 to 25 ppt. The highest mean catch was recorded at the 5 to 9.9 ppt X 30 degrees to 34.9 degrees C (86 degrees to 95 degrees F) cell of the matrix with a mean fish size of 57 mm TL. Collection techniques in this study may have favored the taking of young-of-the-year juveniles. It is possible than that the lower salinities often associated with postlarval and very young Gulf menhaden were under represented.*126* Substrate and System Features: Although Gulf menhaden inhabit the water column and no direct use of the substrate is apparent, they are most often captured over soft bottoms. Christmas (1981) incorporated substrate type as a parameter in his model of habitat suitability for Gulf menhaden with the highest value assigned to mud (vs. mud-sand or sand) substrates. He stated that "substrate is included in the estimate of food value because the esturarine and nearshore marine habitats are shallow; thus currents and wave action will resuspend nutrients and organic detritus which have been incorporated into the sediments....[It was also] assumed that muddy substrates, because of their more dense [prey] populations and absorptive chemical properties, have a higher food value than sandy substrates."*126* Importance of Marsh: Another feature of the Gulf menhaden habitat not mentioned in previous sections is the importance of the surrounding marsh system. Results of a study by Copeland and Bechtel (1974) indicated that menhaden were not frequently found within marsh areas. However, they fully recognized the importance of these areas by stating, "In order to maintain an environment capable of supporting menhaden populations in estuaries, the tributaries, fringes and tertiary bays must be protected from destruction [and]...streamflow, which brings that freshwater required for low salinity maintenance and necessary foodstuffs for the small menhaden, will have to be maintained."*126* Dissolved Oxygen: Gulf menhaden are frequently among the species hardest hit by low dissolved oxygen (DO) "fish kills" in estuarine waters. Post-larvae and juveniles in restricted bays and backwaters are particularly susceptible to such kills as their mobility and capacity to avoid low DO are limited. Christmas (1981) suggested a minimum DO level of 3 ppm although the empirical basis for this number was not given.*126* Depth: Available information on depth and water movement has largely been incorporated into above discussions. Data presented by Roithmayr and Waller (1963) on seasonal change in depth distribution of Gulf menhaden Environment Associations - 2 (DRAFT) - Environment Associations Species menhaden, gulf Species Id M010026 Date 26 AUG 96 generally reflect the annual inshore-offshore migration pattern. Fish were taken from surface to bottom in 2 to 15 m (6 to 48 ft) from June through September; up to 27 m (90 ft) in October and November; from 7 to 33 m (24 to 108 ft), but occasionally to 88 m (288 ft) from December through February; and back to 2 to 26 m (6 to 84 ft), occasionally to 33 m (108 ft), from March through May.*126* Environment Associations - 3
                               (DRAFT) - Life History
                               Species menhaden, gulf
                                 Species Id M010026
                                   Date 26 AUG 96



LIFE HISTORY

PHYSICAL DESCRIPTION: D. 17-21; A. 20-23; P. 14-17; Sc. 36-50; Gr. 40-150. Scales large, in irregular rows; opercular striae long and distinct; predorsal scales enlarged as in other menhaden.*126* Color in life: Body silvery, greenish on back, with dark humeral spot and usually a series of smaller spots behind humeral one; caudal fin with dark margin; other fins often yellowish.*126* REPRODUCTION: The actual spawning event in Gulf menhaden has not been observed. Statements regarding the site and time of spawning are therefore based upon the capture of eggs, larvae, or spent adults. Spawning is reported to occur in open Gulf of Mexico waters from 2 to 128 m (6 to 420 ft) deep, but is apparently concentrated in waters of less than 18 m or 60 ft. Spawning has been reported from October through March, but is suspected to occur, at least in some years, from September through May. Gulf menhaden may spawn up to four or five times during a single spawning season, each time releasing only that fraction of the developing ova which has matured. Separate spawning peaks in late October and March have been suggested, but definitive data are lacking.*126* Eggs of the Gulf menhaden are spherical and float near the surface. Although data on hatching in the Gulf menhaden were not found, the eggs of Atlantic menhaden (B. tyrannus) are reported to hatch within 2 days (at 15 degrees C or 59 degrees F), with yolk sac absoprtion completed within 5 days.*126* BEHAVIOR: Emigration of adults and maturing juveniles from estuarine to open gulf waters has been reported to occur over a wide time span from midsummer through winter. Gulf menhaden were reported to have begun emigrating from Tampa Bay, Florida, in June or July, from Lake Pontchartrain, Louisiana, in August, and from Pensacola Bay, Florida, by September. Peak gulfward migration apparently occurs from October through January. Movement back into inshore waters by surviving members of all age groups following an overwintering and/or spawning season in open Gulf waters occurs early the following spring, i.e., March to April. The redistribution of returning fish is thought to be "by random movement, probably in search of high food concentrations," with the net result being a movement back into the food-rich waters of the estuaries. As Gulf menhaden live to age-III, this cycle may be repeated some two to four times by an individual fish. The described pattern of inshore-offshsore migration is the "normal" pattern, but juveniles and adults have both been taken in inshore areas in all months.*126* Larvae may spend 3 to 5 weeeks in offshore waters before moving through the passes into the estuaries at 9 to 25 mm SL. The reported timing of this Life History - 1 (DRAFT) - Life History Species menhaden, gulf Species Id M010026 Date 26 AUG 96 movement extends from September through May with a peak from December through March. It is uncertain to what extent the movement into the estuaries is an active or passive process. Researchers stated that larval menhaden "require favorable currents to make their way into the estuary." Researchers believe that larval movement is related to water movement, but clearly suggest an active role. Researchers stated that larvae avoid being swept out of the estuary in tidal currents by moving to slower current areas near shore either by swimming, finding favorable currents or both.*126* Postlarvae have been reported in the estuaries from November through June where they then disperse to shallow (0 to 2 m or 0 to 6.6 ft), quiet, low salinity areas near shore. In the estuary, transformation from postlarval to juvenile morphology occurs as the menhaden reach 30 to 33 mm TL.*126* Juveniles. After transformation, juveniles remain in these low salinity, nearshore areas where they travel about in dense schools, often near the surface. This schooling behavior is retained throughout life. The morphological changes associated with transformation are also accompanied by a change in feeding behavior from selective, particulate-feeding carnivory to filter-feeding omnivory. The reported duration of the Gulf menhaden's juvenile stage and their stay in the estuary is variable. Studies have shown that menhaden in the 0 age-class "are incapable of completing gametogenesis prior to the onset of the ensuing spawning season ... [and] do not participate in the annual migration to the spawning grounds in the offshore waters."*126* LIMITING FACTORS: Temperature. Gulf menhaden have been taken in waters from 5 degrees to 34.9 degrees C. Definitive data on thermal optima within this range, upper, and particularly on lower lethal limits are lacking. Avoidance of water temperature above 30 degrees C has been reported.*126* Salinity. While Gulf menhaden have been reported to occur in waters from fresh to hypersaline (0 to 67 ppt), there may be somewhat narrower salinity ranges with which various life stages are associated. Generally, gravid adults, fertilized eggs, and early larvae were associated with the higher salinity gulf and open bay waters. Postlarvae and juveniles appeared to tolerate a wide range, but were most often associated with nearshore, low salinity areas. Non-gravid or developing adults were associated with mid- range salinities of the estuary. Studies have shown that juveniles entered freshwater, but never penetrated far (1.6 km or 1 mi) beyond the interface with low salinity estuarine water. It's been reported that juveniles commonly occurred in waters from 20 to 60 ppt, but also noted mass mortalities of Gulf menhaden at salinities over 80 ppt.*126* Substrate and System Features. Researchers of one study indicated that menhaden were not frequently found within marsh areas. However, they fully recognized the importance of these areas by stating, "In order to maintain an environment capable of supporting menhaden populations in estuaries, the tributaries, fringes and tertiary bays must be protected from destruction Life History - 2 (DRAFT) - Life History Species menhaden, gulf Species Id M010026 Date 26 AUG 96 [and]. . .streamflow, which brings the freshwater required for low salinity maintenance and necessary foodstuffs for the small menhaden will have to be maintained."*126* Dissolved Oxygen. Gulf menhaden are frequently among the species hardest hit by low dissolved oxygen (DO) "fish kills" in estuarine waters. Postlarvae and juveniles in restricted bays and backwaters are particularly susceptible to such kills as their mobility and capacity to avoid low DO are limited. Researchers have suggested a minimum DO level of 3 ppm although the empirical basis for this number was not given.*126* POPULATION ATTRIBUTES: The Fishery. The purse seine fishery for Gulf menhaden dates back to the turn of the century, but only developed into a major industry after World War II. The fishery for this single species today provides over one-quarter of the Nation's commercial fishery landings by weight. In 1979 this fishery ranked first in tonnage landed (779,390 mt-live wt) and seventh in value ($73,426,000, exvessel price) among commercially fished species in the United States. Fishmeal and oil produced from menhaden are in high demand for poultry feed, cosmetics, and margarine. Young menhaden are sometimes used for bait by Mississippi fishermen. The Gulf menhaden is a short-lived species, with age I and II fish constituting the majority of the commercial catch. Fish as old as Age IV are also occasionally taken. An overlap in predation upon the young menhaden by both man and several species of sport fish, led one researcher to comment that there "is considerable speculation that menhaden are being overfished to the detriment of the sport fishery." Since this statement was made in 1965, the commercial menhaden catch has increased considerably while, for at least two menhaden predators, the spotted seatrout and red drum, no clear evidence of a decreasing sport catch has been shown. No studies, however, of trends in abundance of the entire predator assemblage were found. As the menhaden fishery is a very "clean" fishery, there is little direct destruction of other species as discarded by-catch. Fisheries activities extend primarily from 1.6 to 4.8 km (1 to 3 mi) offshore from Florida to eastern Texas and are therefore subject to State rather than Federal regulation. The season runs from mid-April to October when the fish are inshore and sexually inactive. Researchers concluded that Gulf menhaden from Florida to the Yucatan constituted a single, widespread stock. However, the results of tagging studies indicated more of a localization of populations with little movement between fishing grounds east and west of the Mississippi River Delta. Studies show that recruitment of age I menhaden "is dependent on the number of juveniles produced in estuaries in and adjacent to each fishing area." While this association of separate stocks with nearby estuarine systems now seems to be accepted, the relative importance of particular coastal sections as nursery areas is uncertain.*126* LIFE HISTORY CODES - Breeding/Spawning Season: October Breeding/Spawning Season: November Life History - 3 (DRAFT) - Life History Species menhaden, gulf Species Id M010026 Date 26 AUG 96 LIFE HISTORY CODES - Breeding/Spawning Season: December Breeding/Spawning Season: January Breeding/Spawning Season: February Breeding/Spawning Season: March REFERENCES FOR LIFE HISTORY- 126 Life History - 4
                           (DRAFT) - Management Practices
                               Species menhaden, gulf
                                 Species Id M010026
                                   Date 26 AUG 96



MANAGEMENT PRACTICES

RESULT MANAGEMENT PRACTICE Existing Regulating commercial harvest gear types Existing Regulating harvest of species being described Existing Regulating harvest - setting seasons Beneficial Maintaining unique or special habitat features [wetlands, caves, Beneficial Developing/maintaining suitable salinity Beneficial Developing/maintaining stream structures Adverse Draining wetlands, marshes, ponds, lakes REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 126 REFERENCES FOR ADVERSE MANAGEMENT PRACTICES - 126 REFERENCES FOR EXISTING MANAGEMENT PRACTICES - 126 and 192 COMMENTS ON MANAGEMENT PRACTICES - Fisheries activities extend primarily from 1.6 to 4.8 km (1 to 3 mi) offshore from Florida to eastern Texas and are therefore subject to State rather than Federal regulation. The season runs from mid-April to October when the fish are inshore and sexually inactive.*126* The maintenance of large parcels of surrounding marsh and of inflowing freshwater tributary systems is considered necessary to the maintenance of an environment capable of supporting menhaden populations in estuaries. In order to maintain an environment capable of supporting menhaden populations in estuaries, the tributaries, fringes and tertiary bays must be protected from destruction and streamflow, which brings the freshwater required for low salinity maintenance and necessary foodstuffs for the small menhaden, will have to be maintained.*126* Management Practices - 1
                                   (DRAFT) - References
                                  Species menhaden, gulf
                                    Species Id M010026
                                      Date 26 AUG 96



     

References

126* Lassuy, D. 1983. Species Profiles: Life Histories and Environmental Requirements (Gulf of Mexico) -- Gulf Menhaden. U.S. Fish and Wildlife Service Biol. Rep. 82(11.2) pp 13. 192 * Gulf States Marine Fisheries Commission. 1988. The Menhaden Fishery of the Gulf of Mexico United States: A Regional Management Plan. (18)J.Y. Christmas, David J. Etzold, Larry B. Simpson, Stephen Meyers (ed.). Gulf States Marine Fisheries References - 1