218 



Fishery Bulletin 90(2). 1992 



study describes age, growth, and reproduction of this 

 increasingly exploited fish. 



Methods 



Goosefish were collected during the spring and autumn 

 groundfish surveys (1982-85) conducted by the Na- 

 tional Marine Fisheries Service (NMFS) in the Mid- 

 Atlantic Bight and southern New England (for survey 

 methodology see Grosslein and Azarovitz 1982). Addi- 

 tional samples were obtained during the NMFS 1983 

 summer scallop survey off southern New England and 

 during cniises aboard commercial groundfish trawlers 

 and scallopers operating out of Hampton, Virginia. 

 Sampling effort was concentrated in the area from 

 southern New England to Virginia. 



Goosefish greater than ~ 180 mm were examined at 

 sea. Smaller individuals were fixed in 10% formalin and 

 saved for examination in the laboratory. Examination 

 included measuring total and standard length and 

 weight, excising a section of the vertebral column, 

 removing both sagittal otoliths, recording stomach con- 

 tents, macroscopic staging and weighing of the gonads, 

 and preserving pieces of gonads for histological inspec- 

 tion and fecundity estimates. 



Reproduction 



Gonads were staged visually in the field and assigned 

 to one of the following classes: immature, resting, 

 developing, ripe, and spent. Both gonads were then 

 removed from the body cavity and weighed to the 

 nearest O.lg. A small representative piece was excised 

 from the midsection of selected gonads and preserved 

 in Davidson's fixative for histological study. 



Late-developing and ripe ovaries were selected for 

 fecundity analyses. The extremely large size of goose- 

 fish ovaries precluded saving the entire organ. A sub- 

 sample of about lOOg was weighed to the nearest 0.1 g 

 and placed in modified GOson's solution (Simpson 1951). 

 After several months of storage, most of the ovarian 

 connective tissue had dissolved. Ova were removed 

 from the Gilson's solution, separated from any remain- 

 ing ovarian tissue, rinsed in water, blotted on absor- 

 bent paper, and weighed. Three subsamples, each con- 

 taining about 1000 ova, were removed and weighed to 

 the nearest 0.001 g. Ova in each sample were counted 

 using a dissecting microscope. Fecundity was calcu- 

 lated as: 



Fecundity = (W)(P)(N) 



where W = total weight of both ovaries, 



weight of sample after Gilson's 



N = mean number of ova/g from 3 subsamples. 



Gonad portions preserved in Davidson's fixative for 

 histological preparations were dehydrated in a graded 

 series of ethanol baths and Technicon reagents (S-29 

 dehydrant VC-670 solvent). They were then embedded 

 in paraffin, sectioned at Yf^m and stained using Harris' 

 hematoxylin and counterstained with eosin Y. Gonad 

 sections were viewed at 40 x , 100 x , and 400 x to deter- 

 mine stages of oogenesis and spermatogenesis to verify 

 accuracy of macroscopic field staging and to examine 

 the histology of the goosefish ovary. 



A gonasomatic index (GSI) was calculated for each 

 sex as: 



GSI 



gonad weight 

 total weight of fish 



100. 



P = 



weight of sample before Gilson's 



Age and growth 



Weights were taken to the nearest gram in fish < 1200 g 

 and to the nearest 25 g increment in fish > 1200 g. Total 

 length (TL) in millimeters was measured from the tip 

 of the protruding lower jaw to the tip of the caudal fin 

 rays. Because of the large size and loose suspension 

 of the goosefish jaw apparatus, it was necessary to 

 hold the head in a standard position while length was 

 measured to reduce variation due to changes in head 

 and jaw configuration. This position was achieved 

 by applying light pressure to the top of the head, 

 thereby causing a maximal amount of dorsal-ventral 

 compression. 



Vertebrae were chosen as the best method to age 

 L. americanus, based on a preliminary examination 

 which revealed that each vertebral centrum contained 

 concentric rings which appeared to be annuli. Sagittal 

 otoliths were also examined; however, otoliths from 

 larger fish were opaque and had extremely irregular 

 outer margins, which made it difficult or impossible to 

 discern annuli. 



A section of the vertebral column containing verte- 

 brae numbers 3-11 was excised from each goosefish. 

 These were stored in 50% isopropanol for 1-12 months. 

 Vertebrae numbers 7-10 were similar in size and shape 

 and also had the largest diameters. Vertebra number 

 8 was used in aging, but number 9 was used if number 

 8 was damaged in preparation. 



Vertebra number 8 was disarticulated from the rest 

 of the excised vertebral section. The neural and haemal 

 arches and all excess fat, muscle, connective tissue and 

 cartilage were removed by scalpel. The vertebra was 

 then sliced along the midsagittal line producing two 

 hourglass-shaped halves, similar to the method used by 

 Lyczkowski (1971) and Lawler (1976) for preparing 

 vertebrae from northern puffer Sphaeroides maculatus 



