Skinner Christina, Newman Steven P, Box Stephen, Narozanski Andrzej, Polunin Nicholas V C
School of Natural and Environmental Sciences, Marine Science, Ridley Building, Newcastle University, Newcastle upon Tyne, UK.
Banyan Tree Marine Lab, Vabbinfaru, Republic of the Maldives.
J Fish Biol. 2019 Apr;94(4):585-594. doi: 10.1111/jfb.13939. Epub 2019 Mar 20.
The grazing behaviour of two Caribbean parrotfish, a fished species, the stoplight parrotfish Sparisoma viride and a non-fished species, the striped parrotfish Scarus iseri, were studied in the presence (fished site) and absence (marine reserve) of chronic spearfishing activity. Diurnal feeding periodicity did not differ between the sites in either species: roving individuals had significantly higher bite rates in the afternoon, while territorial individuals foraged consistently throughout the day. Mean bite rate varied between sites in both species. Abundance, biomass and bite rates of S. viride were all significantly higher within the reserve, except for roving S. viride which had a higher mean bite rate in the afternoon outside the reserve compared with within it, attributable to maximisation of feeding in the afternoon when fishing risk was lower. Scarus iseri mean abundance and bite rate were greater outside the reserve, potentially because reduction in large territorial herbivores allowed S. iseri to feed more rapidly. By reducing the grazing potential of the remaining S. viride individuals the effect of fishing is greater than would be predicted from biomass changes alone. Less grazing by S. viride would not be compensated for by the increase in grazing by S. iseri because the latter feeds on different algae. Spearfishing of key parrotfish species reduces grazing potential directly by extraction and indirectly by changing behaviour.
研究了两种加勒比鹦鹉鱼的摄食行为，一种是被捕捞的物种——绿唇鹦嘴鱼（Sparisoma viride），另一种是未被捕捞的物种——条纹鹦嘴鱼（Scarus iseri），研究是在存在长期鱼叉捕鱼活动的情况下（捕捞区域）和不存在这种活动的情况下（海洋保护区）进行的。两种鱼在不同区域的日间摄食周期没有差异：游动个体在下午的咬食率显著更高，而领地性个体则全天持续觅食。两种鱼在不同区域的平均咬食率有所不同。绿唇鹦嘴鱼在保护区内的数量、生物量和咬食率均显著更高，但游动的绿唇鹦嘴鱼除外，其在保护区外下午的平均咬食率高于保护区内，这是因为在下午捕鱼风险较低时摄食最大化。条纹鹦嘴鱼在保护区外的平均数量和咬食率更高，这可能是因为大型领地性食草动物数量减少，使条纹鹦嘴鱼能够更快地觅食。通过降低剩余绿唇鹦嘴鱼个体的摄食潜力，捕鱼的影响大于仅根据生物量变化所预测的影响。绿唇鹦嘴鱼摄食量的减少不会被条纹鹦嘴鱼摄食量的增加所补偿，因为后者以不同的藻类为食。对关键鹦鹉鱼物种的鱼叉捕鱼直接通过捕捞减少了摄食潜力，间接通过改变行为减少了摄食潜力。
