Effect of Hook and Bait Size on Catch Efficiency in the Persian Gulf Recreational Fisheries

Abstract

The effect of hook and bait sizes on the catch efficiency and size composition of Spangled Emperor Lethrinus nebulosus, Orange-spotted Grouper Epinephelus coioides, and Narrowbarred Mackerel Scomberomorus commerson was investigated in the recreational and semi-subsistence handline fishery in the Persian Gulf. Based on expectations that increasing hook and bait sizes would decrease the catch efficiency of the smaller individuals while maintaining the catch efficiency of larger fish, we investigated the effect of increasing hook and bait sizes. For all three species, the results indicated slightly lower catch efficiency for the smaller fish when larger hooks were used. Furthermore, the results demonstrated a significant increase in catch efficiency for the larger sizes of Spangled Emperor and Orange-spotted Grouper when fished with larger hooks, an effect that increased with fish size for both species. Additionally, the overall catch efficiency did not vary significantly when increasing hook and bait sizes for the three species investigated. This study shows that fishing with larger hooks and larger bait would change the exploitation pattern of these species toward higher proportions of larger fish in the catches. Moreover, based on the size distribution of the species on the fishing grounds during the study period, the use of larger hooks and bait would lead to significant increases in the total number of Spangled Emperor caught (41% increase; 95% confidence interval [CI] = 17-69%) and the total number of Orange-spotted Grouper caught (151% increase; 95% CI = 132-336%), respectively. The results indicated a similar effect for Narrowbarred Mackerel; however, the effect was far less profound than for the two other species and was not significant for any size-classes.

The effect of artificial lure type and environment conditions on the short‐time post‐release mortality of two recreational fished Luciobarbus species

“…This study evinced that size of L. mysteceus and L. esocinus caught by angling from the Keban Dam Lake was a function of lures size, which are in line with findings of previous studies (Arlinghaus et al, 2008;Eighani et al, 2018;Orsi, 1987). This study found that increasing lure size substantially reduces the catch rate of undersized fishes, which are consistent with the previous findings for other fish species (Alós et al, 2008;Ateşşahin et al, 2015;Herrmann et al, 2018;Otway & Craig, 1993). In this study, a significant relationship was also detected between the lures colour and size structure of L. mysteceus though this relationship was not significant in L. mysteceus.…”

“…. Accordingly, the use of larger hooks can also substantially reduce the catch rates of undersized fish (Alós et al, 2008;Ateşşahin et al, 2015;Herrmann et al, 2018;Otway & Craig, 1993).…”

Effect of pot design on the catch efficiency of snow crabs (Chionoecetes opilio) in the Barents Sea fishery

“…Using the numbers and sizes of snow crabs caught in test and standard pots in each set, we determined whether there was a significant difference in the catch efficiency averaged over deployments between the test pot and standard pot types. Specifically, we assessed the relative length-dependent catch efficiency effect of changing from standard pots to moon pots using the method described in Herrmann et al [31] and compared the catch data for the standard and the test pots. This method models the size-dependent catch comparison rate ( CC w ) summed over sets: where ns wj and nt wj are the numbers of snow crabs caught in each size class w in a standard pot and a test pot in set j .…”

“…The confidence intervals for the catch comparison curve and catch ratio curve were estimated using a double bootstrapping method [31, 34]. This bootstrapping method accounts for between-set variability (the uncertainty in the estimation resulting from set variation of catch efficiency in the pots and in the availability of snow crabs) as well as within-set variability (uncertainty about the size structure of the catch for the individual sets).…”

Temporal variation, population and growth parameters of swordfish (Xiphias gladius Linnaeus, 1758) in the nearshore waters of Kenya

“…The results indicate that seasonality partly influenced the catch rates of swordfish in the Kenyan coastal waters. This temporal distribution of the swordfish catches and abundance could be partly attributed to the seasonal changes in the temperature of the sea water, sex and size of the individual fish, and availability of food in the environment (Mueni et al, 2019;Lan et al, 2014;and Ward and Elscot, 2000) and the type of fishing gears (Herrmann et al, 2018;and Tuda et al, 2016). The high catch rates seem to coincide with the spawning season (October through to April) for swordfish in the Indian Ocean (Lan et al, 2014;and IOTC, 2017).…”