Table 15. (Concluded.) 



Date 



Station 



IC 



Offshore 



IB 



Inshore 



Little 



St. George 



lA 



ichthyoplankton (25.8 m"'') 

 beyond Sike's Cut in April. 



are found iust 



Fishes that live in a qiven estuary 

 can be organized into various categories 

 according to their life history (McHugh 

 1^67). Estuarine-deoendent forms include 

 truly estuarine species, anadromous and 

 catadromous soecies, marine soecies that 

 live and often spawn offshore but use the 

 estuarv as a nursery, and marine species 

 that enter the estuary seasonally as 

 adults but remain offshore as juveniles. 

 Tn the Apalachicola estuarv, the estuarine 

 eggs and larvae are dominated by one 

 estuarine species, the bay anchovy. At 

 stations that are not near the passes (3, 

 2, 1; Table 15) numbers of larvae of 

 species other than anchovies are usually 

 low. Such areas tend to be dominated by 

 species that spawn within the estuary 

 (i.e., atherinids, blennies, skilletf ish). 

 Blanchet (1^78) attributed the low number 

 of eggs in the estuary to the flushing of 

 the bay system. It is also possible that 

 the generally low salinities within the 

 estuary prevented spawning by most 

 species. Overall, the pattern and 

 distribution of the fish larvae within the 

 bay system would indicate that, while 

 specific causative factors remain unknown, 

 the primary function of the bay is its use 

 as a nursery by true estuarine soecies and 

 marine species that soawn offshore. 



4.3. BENTHOS 



Considerable information is available 

 concerning benthic macroinvertebrates in 



estuarine and coastal systems (Mann 1P82). 

 Benthic infauna, which live within the 

 sediments, are usually separated according 

 to size into macrobenthos, meiobenthos, 

 and microbenthos. Although there are 

 differing opinions as to the exact 

 dimensions of each size category, most 

 workers agree that the macrobenthos 

 includes those organisms taken in 250-500 

 micrometer ( m) sieves. Meiobenthic 

 organisms are those taken between 62 m 

 and 250 m, and organisms 

 m are classified as 

 Macroinvertebrates living 

 sediments or at the 

 interface are called 

 eoi benthic invertebrates, 

 will be treated as nekton 



smaller than 62 



microbenthos. 



just above the 



sediment-water 



epifauna or 



These organisms 



in this review. 



The relative composition of any given 

 benthic macroinvertebrate collection 

 depends to a considerable degree on the 

 form of sampling gear. In the 

 Aoalachicola Bay system, benthic 

 macroinvertebrates have been taken by 

 cores and ponars (McLane 1980; Mahoney and 

 Livingston li^S?), leaf packs (Livingston 

 et al. 1977), otter trawls (Livingston 

 1976a, b; Livingston et al . lQ76b), and 

 dredge-nets and seines (Purcell 1P77), 

 The benthic macroinvertebrates in the 

 Apalachicola Bay system represent a 

 diverse fauna (Table 16) with distinct 

 oatterns of temporal and spatial 

 distribution (Livingston et al. 1^77). 

 Although considerable seasonal and year- 

 to-year variation in species composition 

 and relative abundance is found at any 

 given sampling area, certain trends are 



49 



