854 



Preliminary examination of the match-mismatch 

 hypothesis and recruitment variability of 

 yellowtail flounder, Limanda ferruginea 



Donna L. Johnson 



James J. Howard Marine Sciences Laboratory at Sandy Hook 



Northeast Fisheries Science Center 



National Marine Fishenes Service, NOAA 



74 Magruder Road 



Highlands, New Jersey 07732 



E-mail address. Donna Johnsonia'noaa. gov 



exist and spawn on Georges Bank 

 (GB) and off Southern New England 

 (SNE) and to observe any correlation 

 between year-class strength and prey 

 abundance. Data from a comprehen- 

 sive sampling program, the Marine 

 Resources Monitoring, Assessment, and 

 Prediction ( MARMAP I, structured with 

 broad temporal and geographic cover- 

 age, were used for this study. Collec- 

 tions were made during 1977-87 on 

 the U.S. continental shelf from Cape 

 Hatteras to the Gulf of Maine. 



Underlying explanations of recruit- 

 ment variation among fish stocks have 

 been an issue for several decades. An 

 understanding of biological relation- 

 ships between larval fish and their 

 zooplankton prey is needed for inter- 

 preting recruitment success. Recruit- 

 ment fluctuations often depend upon 

 events occurring during a critical period 

 between spawning and the time of first 

 feeding by larvae (Hjort, 1914). Condi- 

 tions affecting these early life stages 

 will also determine the number of indi- 

 viduals that survive in a year class. The 

 timing of spawning can enhance the 

 spatial and temporal affinity between 

 lai-vae and their food resources (Hjort, 

 1914: Gushing, 1975, 1990; Gushing 

 and Dickson, 1976). 



Once resorption of the yolk sac is 

 complete by yolksac lai-\'ae, their sur- 

 vival depends entirely upon the amount 

 and accessibility of available food. If 

 sufficient prey is not located after the 

 yolk sac has become exhausted, perma- 

 nent degeneration of the larva's diges- 

 tive system will occur (Pitcher and 

 Hart, 1983). Not only are early stage 

 larvae and young juveniles vulnerable 

 because of their dependence on nour- 

 ishment, they are also susceptible to 

 movement caused by ocean currents 

 (Hjort, 1914, 1926), predation, and star- 

 vation (Houde, 1987). 



Yellowtail flounder {Limanda ferru- 

 ginea) is an economically important 

 species that experiences marked varia- 

 tion in year-class strength. In the pres- 

 ent study, time series data offish eggs, 

 lai"vae, and zooplankton were used to 

 determine if a match or mismatch 

 in time and space between yellowtail 

 flounder production and its potential 



prey existed from Georges Bank and 

 Southern New England 1977 through 

 1987. Gushing (1975; 1990) hypothe- 

 sized that links (matches or misses) 

 in time and space among phytoplank- 

 ton blooms followed by zooplankton 

 and then larval fish lead to year-class 

 variability. A match occurs when there 

 is a close overlap between production 

 curves of fish larvae and their plank- 

 tonic prey; conversely, a mismatch 

 occurs when there is an extensive tem- 

 poral difference ( Fig. 1) (Gushing, 1975; 

 1990). A match of peak occurrences 

 would presumably result in a success- 

 ful year class owing to adequate feed- 

 ing and gi-owth, and increased chances 

 for survival if other sources of mortal- 

 ity and loss are constrained. 



Yellowtail flounder became a key 

 constituent of the U. S. demersal fish- 

 ery in the early 1930s as a result 

 of stock declines in winter flounder 

 (Royce et al., 1959). There were subse- 

 quent drastic reductions in populations 

 and catches during the early 1970s 

 in Southern New England (SNE) and 

 the mid-1970s in Georges Bank (GB). 

 In SNE stocks, landings declined from 

 3.5 metric tons (t) in 1970 to 1.5 t 

 in 1975. The abundance of New Eng- 

 land groundfish declined by 65*^ from 

 1977 to 1987 (NEFC, 1991). Three 

 stocks — haddock, redfish, and yellow- 

 tail flounder — reached record low levels 

 by the late 1970s. 



The present study is the first attempt 

 to examine intei'annual variability in 

 yellowtail recruitment in the context of 

 the match-mismatch hypothesis. The 

 goal of this study was to test the pre- 

 diction of the match-mismatch hypoth- 

 esis for yellowtail flounder stocks that 



Materials and methods 



A total of 2496 stations from the 

 western North Atlantic were sampled 

 during an eleven-year period from 1977 

 to 1987. At each station fish eggs, 

 larvae, and zooplankton were collected 

 with a bongo frame (diameter at the 

 mouth of net: 61 cm) (Posgay and 

 Marak, 1980) fitted with 0.333-mm 

 and 0.505-mm mesh nets and a 45 kg 

 depressor. The volume of water filtered 

 by each net was measured by flowme- 

 ters suspended in the center of the net 

 mouth. The plankton nets were low- 

 ered at a rate of 50 meters per minute, 

 to within 5 meters of the bottom or to 

 a maximum depth of 200 meters, and 

 retrieved at a rate of 20 meters per 

 minute: nets were towed at 1.5 knots 

 at a 45-degi'ee angle. Net contents 

 were preserved in a mixture of 5'^ for- 

 malin and ocean water. Lai"vae were 

 measured to within 0.1-mm length 

 increments. For complete descriptions 

 of MARMAP sampling procedures see 

 Sibunka and Silverman ( 1984, 1989). 



For each station, catch values were 

 standardized to the number of individ- 

 uals under 10 m- surface area. The 

 delta distribution (Aitchison, 1955) pro- 

 vided unbiased estimates of sample 

 means (Berrien et al., 1981; Penning- 

 ton, 1983). The abundance and distri- 

 bution patterns of yellowtail flounder 

 eggs and larvae were monitored and 

 compared with those of Calanus and 

 Pseudocalanus prey species in the GB 

 and SNE regions from 1977 to 1987. 



Although feeding habit studies of 

 yellowtail larvae have not been docu- 



Manuscript accepted 8 May 2000. 

 Fi.sh. Bull. 98:8.54-86.3 (2000). 



