years. Life history, distribution, commercial 

 catch analysis, and some aspects of natural 

 behavior are priority items. 



Some of the immediate questions to be an- 

 swered are as follows: 



1. How long do thread herring live, and how 

 fast do they grow? 



2. What year classes make up the commer- 

 cial catch, particularly during the early stages 

 of the developing fishery? 



3. When and where does spawning occur, 

 and what areas serve as nurseries? 



4. Do thread herring migrate, and if so, 

 what are seasonal patterns? 



5. How does water temperature affect the 

 distribution of stocks? 



6. What factors affect vertical distribution 

 of fish and schools of fish? 



7. Do game fish feed on thread herring, and 

 if so, to what extent? 



FACILITIES AND PROCEDURES 



The R/ V Kingfish is equipped with a hydraulic 

 power block for fishing monofilament gill nets 

 of various mesh sizes. Adult fish are sampled 

 in Tampa Bay, Charlotte Harbor- Pine Island 

 Sound, and nearshore Gulf waters between the 

 two estuaries. At each gill net station, plankton 

 tows are made for eggs and larval fish, and 

 oceanographic data are recorded. Beach seines 

 and lift nets were used to collect junvenile 

 thread herring in shallow areas and near docks 

 and bridges. 



We have collected samples of the catch of 

 commercial vessels since the beginning of 

 the fishery. Commercial fishermen have co- 

 operated in providing samples from purse 

 seine catches along with information on fishing 

 effort and areas of operation. Fishing logbooks 

 have been placed aboard all vessels engaged 

 in the fishery. 



Conversion of part of a dockside warehouse 

 gave us a new laboratory for processing fish 

 samples. Laboratory processing of fish sann- 

 ples includes measurements of body length 

 and depth, body weight, and where applicable, 

 gonad weight. Fish are sexed, and scales, 

 stomach, and gonad samples preserved for 

 future analysis. Samples from our fishing 

 operations and from commercial catches re- 

 ceived the same treatment. 



A through-flow sea-water system is avail- 

 able for holding live fish. Attempts are being 

 made to hold fish for long periods to provide 

 data for age and growth studies and for ex- 

 periments in artificial fertilization. 



PROGRESS DURING THE YEAR 



The highlights of research results during 

 the first year are as follows: 



1. Analyses of connmercial catches landed 

 at the Protein Products plant showed that 



food fish taken incidentally in thread herring 

 purse seine sets did not exceed about 0.35 

 percent (by weight) of the total catch. At court 

 hearings on the food fishproblem, we presented 

 these data along with opinions stating that the 

 thread herring fishery would have no significant 

 adverse effects on stocks of food and sport 

 fish. As a result, the court delivered a 

 declaratory judgment permitting the taking of 

 a small amount (unofficial agreement is 1 

 percent) of food fish in purse seining for 

 nonfood fish. Testimony given has thus been 

 instrunnental in assuring the continued growth 

 and development of the thread herring fishery 

 on the Florida west coast. 



2. Thread herring catches per unit of effort 

 (30-minute set with a 5.1-cm. mesh, 30.5 m. 

 by 3.1 m. monofilament gill net) in Gulf waters 

 off St. Petersburg Beach reached a peak in 

 late spring and early summer and declined 

 with falling water temperatures in the fall. 

 Very few thread herring were taken during 

 the winter (fig. 17). When coastal waters cool, 

 the thread herring concentrate in the south, 

 and when the waters warm, the fish disperse 

 to the north, and possibly offshore. 



3. Catch per set by commercial vessels 

 off Fort Myers reached a peak in winter and 

 declined with the warming of coastal waters 

 in the spring. Warming water and possibly 

 factors associated with warming water, such 

 as feeding and spawning habits, seem to affect 

 the schooling behavior of thread herring. In 

 the warmer months many surface schools 

 occur off Fort Myers, but individual schools 

 contain fewer fish than in the cooler months. 

 Purse seine sets therefore produce fewer fish 

 in the summer. 



4. Juvenile thread herring appeared in 

 beach seine samples along Gulf beaches in the 

 Tampa Bay area in July and disappeared by 

 October. 



Figure 17. — Mean number of thread herring caught per 

 set of a 30.5-m„ 5.1-cm. mesh monofilament gill net 

 In Gulf waters off St. Petersburg Beach. 



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