Responses of Cod (<i>Gadus morhua</i>) and Haddock (<i>Melanogrammus aeglefinus</i>) to Baited Hooks in the Natural Environment

Løkkeborg, Svein; Bjordal, Åsmund; Fernö, Anders

doi:10.1139/f89-189

Cited by 89 publications

(67 citation statements)

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Section: Discussionsupporting

confidence: 55%

“…While we did not directly ob serve the behaviors of fishes in proximity to our sampling gear, time-of-capture data for great barracuda directly support the validity of our assumption in that great barracudas were not motivated to feed outside of their normal feeding times. Given this conclusion and the findings of Løkkeborg & Bjordal (1989), we assert our data reflect the natural feeding patterns of the shark species we examined and believe our assumption is valid.It has been stated that to properly estimate the feeding chronology of a given shark species one must employ stomach content analyses where individual meal times are reconstructed using qualitative stateof-digestion scales (Wetherbee & Cortés 2004). While we agree that analyses of stomach contents provide valuable insight into the feeding chronology of sharks, we consider our methodology to be complimentary and, in some respects, more powerful.…”

supporting

confidence: 55%

“…ingestion or approach) during dark hours. This result led Løkkeborg & Bjordal (1989) to conclude that differences in ob served behaviors resulted from diel variation in feeding motivation. While we did not directly ob serve the behaviors of fishes in proximity to our sampling gear, time-of-capture data for great barracuda directly support the validity of our assumption in that great barracudas were not motivated to feed outside of their normal feeding times.…”

Section: Discussionmentioning

confidence: 99%

“…While species-specific trends in times-of-capture were identified, the validity of our findings is contingent upon whether or not the presence of baited hooks motivates fishes to alter their natural behavior and feed during non-foraging periods. To our knowledge, no studies have examined the influence of baited hooks on chondrichthyan feeding motivation; however, Løkkeborg & Bjordal (1989) investigated the effect of baited hook exposure on the feeding motivation of 2 teleost species. Using underwater television, the authors directly observed that when exposing cod Gadus morhua and haddock Melanogram mus aeglefinus to baited hooks throughout the diel cycle, a significantly lower percentage of individuals responded (e.g.…”

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confidence: 99%

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Feeding chronology of six species of carcharhinid sharks in the western North Atlantic Ocean as inferred from longline capture data

Driggers¹,

Campbell²,

Hoffmayer³

et al. 2012

Mar. Ecol. Prog. Ser.

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Time-at-capture data for 6 species of carcharhinid sharks were collected during 2692 fishery-independent longline sets conducted in the western North Atlantic Ocean from 1995 through 2009. As operations occurred continuously throughout the diel cycle, time-at-capture data were used as a proxy for natural feeding behavior to examine the diel feeding chronology of blacknose Carcharhinus acronotus, spinner C. brevipinna, bull C. leucas, blacktip C. limbatus, sandbar C. plumbeus, and Atlantic sharpnose Rhizoprionodon terraenovae sharks. All 6 species were collected during all hours of the diel cycle; however, application of circular statistics revealed that spinner, bull, blacktip and sandbar sharks increased their feeding activity during nocturnal hours. Atlantic sharpnose and blacknose sharks exhibited no significant directedness in time-ofcapture, indicating that these 2 species lack distinct feeding patterns. The species-specific differences in feeding chronologies of the sharks examined demonstrate that broad generalizations concerning the feeding behavior of sharks are not appropriate. KEY WORDS: Chondrichthyes · Elasmobranch · Carcharhinidae · Diel behavior Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 465: [185][186][187][188][189][190][191][192] 2012 in gill nets throughout the diel cycle. When grouping their stomach content weight data into 3 h intervals the authors determined feeding activity was generally highest during the day; however, when grouping data into 4 h intervals, peak feeding generally occurred in the afternoon and night.Telemetry data have also been used to infer diel feeding patterns in several shark species; however, such information can also lead to ambiguous conclusions as increased movements, often assumed to be indicative of foraging, could be related to non-feeding behaviors such as movements within an individual's home range or between foraging areas (Heithaus 2004). For example, Sciarrotta & Nelson (1977) tracked 14 blue sharks Prionace glauca in the eastern Pacific Ocean and found these sharks to be most active during nocturnal periods, as indicated by increased frequency of dives through the water column. This finding led the authors to conclude that while blue sharks feed during all hours of the day, peak feeding occurs at night; however, based on analyses of stomach contents, Kubodera et al. (2007) concluded that blue sharks in the western Pacific Ocean feed primarily during the day.While analyses of stomach content and telemetry data have provided valuable information on the feeding chronology of sharks, an overlooked method of examining diel feeding activity is the use of baited hooks which, with the exception of foul hooking, require that a shark voluntarily approach and actively attempt to feed in order to be captured. To our knowledge, only 2 studies have investigated diel trends in catch rates, albeit briefly, of a shark species using baited gear (Medved & Marshall 1981, Heithaus 2001. If soak times are limi...

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Section: Discussionsupporting

confidence: 55%

supporting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Feeding chronology of six species of carcharhinid sharks in the western North Atlantic Ocean as inferred from longline capture data

Driggers¹,

Campbell²,

Hoffmayer³

et al. 2012

Mar. Ecol. Prog. Ser.

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“…Over the last 60 years, underwater video technology has been successfully applied to a wide variety of objectives (Cappo, 2010;Mallet & Pelletier, 2014), including the assessment of reef fishes (e.g., Gardner & Struthers, 2012;Harvey et al, 2012), sharks (Brooks et al, 2011), deep-water scavengers (Priede et al, 1990(Priede et al, , 1994, and epibenthic invertebrates (Stokesbury et al, 2004;Harris & Stokesbury, 2006); the survey of marine habitats (Koenig et al, 2005;Carbines & Cole, 2009); and the analysis of behavior in different taxa (e.g., Løkkeborg et al, 1989;Albert et al, 2003), among other uses. A wide variety of camera configurations (from single cameras to stereo-video) were used for these purposes, both mounted onto static tethered or remote frames (baited and non-baited underwater video stations) and attached to mobile devices (remotely operated vehicles or ROVs, sleds and drifting cameras) (Shortis et al, 2009a;Cappo, 2010;Mallet & Pelletier, 2014).…”

Section: Introductionmentioning

confidence: 99%

A novel method to obtain accurate length estimates of carnivorous reef fishes from a single video camera

Trobbiani

Venerus

2015

Neotrop. ichthyol.

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In the last years, technological advances enhanced the utilization of baited underwater video (BUV) to monitor the diversity, abundance, and size composition of fish assemblages. However, attempts to use static single-camera devices to estimate fish length were limited due to high errors, originated from the variable distance between the fishes and the reference scale included in the scene. In this work, we present a novel simple method to obtain accurate length estimates of carnivorous fishes by using a single downward-facing camera baited video station. The distinctive feature is the inclusion of a mirrored surface at the base of the stand that allows for correcting the apparent or "naive" length of the fish by the distance between the fish and the reference scale. We describe the calibration procedure and compare the performance (accuracy and precision) of this new technique with that of other single static camera methods. Overall, estimates were highly accurate (mean relative error = -0.6%) and precise (mean coefficient of variation = 3.3%), even in the range of those obtained with stereo-video methods.En los últimos años, los avances tecnológicos permitieron intensificar el uso de estaciones de video fijas para estudiar la abundancia, composición de especies y estructura de tamaños de los ensambles ícticos. Sin embargo, la utilización de una única cámara estática para estimar el tamaño de los peces puede conducir a determinaciones poco exactas, provocadas por la distancia variable entre los peces y la escala de referencia incluida en la escena. En este trabajo presentamos un método novedoso para obtener estimaciones exactas del largo de peces carnívoros, que utiliza una estación de video fija con una única cámara orientada verticalmente. La característica que distingue a este sistema es la inclusión de una superficie espejada en la base del soporte de la cámara que permite corregir la longitud aparente o "naive" en función de la distancia entre los peces y la escala de referencia. En este trabajo describimos el procedimiento de calibración y comparamos el rendimiento de esta técnica (exactitud y precisión) con la de otros métodos que utilizan una única cámara estática. Las estimaciones obtenidas fueron exactas (error relativo promedio = -0,6%) y precisas (coeficiente de variación promedio = 3,3%), en el rango de valores obtenidos con estéreo-video.

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The Role of Fish Learning Skills in Fisheries and Aquaculture

Fernö¹,

Huse²,

Jakobsen³

et al. 2006

Fish Cognition and Behavior

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Responses of Cod (Gadus morhua) and Haddock (Melanogrammus aeglefinus) to Baited Hooks in the Natural Environment

Cited by 89 publications

References 0 publications

Feeding chronology of six species of carcharhinid sharks in the western North Atlantic Ocean as inferred from longline capture data

Feeding chronology of six species of carcharhinid sharks in the western North Atlantic Ocean as inferred from longline capture data

A novel method to obtain accurate length estimates of carnivorous reef fishes from a single video camera

The Role of Fish Learning Skills in Fisheries and Aquaculture

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