Class Exercise

Hypothetical Class Data

The hypothetical “Real Data” discussed in class lecture showed catches for age-0 to age-5 fish of 77, 111, 126, 104, 81, and 64. Enter these data into a data frame and compute the instantaneous and annual mortality rates.

 

Snapper Mortality

Australian Snapper (Chrysophrys auratus; sometimes referred to as Silver Seabream) were captured from Hauraki Gulf (Auckland, New Zealand) in research trawl surveys at two separate locations (KAH8810 and KAH0012). Length was measured to the neared cm for all captured fish and fish were haphazardly sampled for annual ages estimated from thin-sectioned otoliths. The researchers hoped to assess the mortality rate for the stocks of Snapper at both locations. Data from all fish at both locations is in SnapperHG1.csv (Data, Meta). You should compute the mortality rate for Snapper captured at KAH8810.