Table I. — Longiine cruises yielding swordfish for mercury analysis. 



Designation 



Date 



Coryphaena hippunis; 1 long nose lancetfish, 

 Alepisauntsferox; 14 blue sharks, Prionace glauca; 

 4 sickle sharks, Carcharhinus falciformis: 1 dusky 

 shark, C. obscurus; 2 tiger sharks, Galeocerdo 

 cuvieri; 2 scalloped hammerhead sharks, Sphyrna 

 lewini; 2 mako sharks, Isurus oxyrinchus; 1 por- 

 beagle shark, Lamiui nasus: and 4 unspecified 1am- 

 nid sharks). The size range of the organisms and total 

 mercury content of the dorsal muscle are shown in 

 Table 2. Similar data for a single white shark 

 (Carcharodon carcluirias) obtained in an otter trawl, 

 and two basking sharks {Cetorhiniis ma.ximiis) taken 

 from herring weirs in Passamaquoddy Bay, are also 

 included in Table 2. In addition, mercury determina- 

 tions were completed on 235 specimens of 12 species 

 offish taken from swordfish stomachs (Table 3). 



DISCUSSION 



The areas of capture can be divided into five parts; 

 four divisions of the longiine fishery and a fifth area 

 to the south; the latter includes the Bahamas and 

 eastern Caribbean. The captures in the northern di- 

 visions were made during four cruises in the period 

 July-October 1971. Captures from the southern area 

 were made in February and March 1972. The divi- 

 sions of the swordfish longiine fishery are shown in 

 Figure 1 , while the dates of fishing are given in Table 

 1. 



Mercury levels found in swordfish tissue (dorsal 

 muscle) were tabulated (Table 4) by localities and 

 months. 



Variation With Size 



The slopes, correlation coefficients and "/" val- 

 ues obtained by application of the least squares fit 

 for linear relation between fork length (x) and mer- 

 cury content ly) are included in Table 4. It is appar- 

 ent that there is a relationship, although considera- 

 ble scatter exists. 



Table 2. — Total mercury level (ppm) of dorsal muscle 

 tissue of selected pelagic species. 



155 



