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Diel Reproductive Periodicity of Haddock in the Southwestern Gulf of Maine
Abstract and Figures
We studied a population of Haddock Melanogrammus aeglefinus in the Gulf of Maine to determine whether it exhibits diel spawning periodicity. Commercial fishing vessels were chartered for 25 dedicated long-lining trips to collect sexually mature Haddock in the Stellwagen Bank National Marine Sanctuary at locations identified by commercial fishers as having spawning aggregations. In order to examine diel effects on Haddock reproduction, the changes in CPUE and percentages of male and female Haddock of all reproductive maturity stages, as well as gonadosomatic index (GSI), were observed across a 24-h diel cycle. The comparison of diel patterns among different maturation stages was used to differentiate diel periodicity due to spawning from feeding behavior. Diel periodicity was observed for the proportion of males and females in the catch, the proportion and CPUE of male and female maturation stages most indicative of imminent spawning, and for female GSI. Although spawning occurred throughout the diel cycle, peak spawning of females occurred during the evening hours (1700–2100 hours) and gradually declined to low values during the day at 0900 hours. In an apparent contradiction male spawning stages were uniformly high except for lows during the night between 2100 and 0100 hours. We hypothesize that this pattern is consistent with lekking behavior where strong competition among spawning-ready males during courtship would reduce their feeding activity during the peak spawning hours. Strong annual differences in diel periodicity may have resulted from different temporal patterns in the spawning season or density dependence, or both.
http://www.tandfonline.com/eprint/Ba3RxfhDHjaC9rfM58kw/full
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... We did not fi nd an ovarian maturity index in the literature that categorized the progression in percentage of hydrated oocytes in a gonad. We were interested in whether the increase in percentage of hydrated oocytes was detectable over time and whether these stages may aid in examination of diel reproductive periodicity (Anderson, 2011). is an ovary where a batch of oocytes is in the early phase of OM and when <25% of that ovary's visible surface contains translucent, hydrated oocytes (Table 1). is an ovary where a batch of oocytes is in the middle phase of OM and when 25– 50% of that ovary's visible surface contains translucent , hydrated oocytes (Table 1).Table 1). ...
... tive maturity of Haddock sampled in the southwestern region of the Gulf of Maine in the spring of 2006 and 2007. Hydration stage 1 (H1), hydration stage 2 (H2), and hydration stage 3 (H3) represent early-to-late progression of final oocyte maturation (OM) of a batch of oocytes, based on the percentage of hydrated oocytes present . *=spawning event.Anderson, 2011). Each longline was fi shed with 150 to 400 circle hooks set 2 m apart for an average soak time of 2 h. The number of hooks fi shed per line on each trip was dependent on the success of catching Haddock that day. With the intent of sampling at least 50 Haddock from each longline set, the number of hooks was increased if the sample size ...
... Histological analysis verifi ed that H3-stage ovaries were in a state where the next batch of oocytes to be spawned were in fi nal OM phase (GVBD), with most oocytes fully hydrated. This consistent result is important because both the fi eld H3 and histological 3.3 stages can be confi dently used to identify spawning readiness, and, therefore, we concluded that they will be well suited for use in studies of diel spawning periodicity in Haddock (Anderson, 2011) and other fi shes. ...
We build on recent efforts to standardize maturation staging methods through the development of a field-proof macroscopic ovarian maturity index for Haddock (Melanogrammus aeglefinus) for studies on diel spawning periodicity. A comparison of field and histological observations helped us to improve the field index and methods, and
provided useful insight into the reproductive biology of Haddock and other boreal determinate fecundity species. We found reasonable agreement between field and histological methods, except for the regressing and regenerating stages (however,
differentiation of these 2 stages is the least important distinction for determination of maturity or reproductive dynamics). The staging of developing ovaries was problematic
for both methods partly because of asynchronous oocyte hydration during the early stage of oocyte maturation. Although staging on the basis of histology in a laboratory is generally more accurate than macroscopic staging methods in the field, we found that field observations can uncover errors in laboratory staging that result from bias in sampling unrepresentative portions of ovaries. For 2 specimens, immature ovaries observed during histological examination were incorrectly assigned as regenerating during macroscopic staging. This type of error can lead to miscalculation of length at maturity and of spawning stock biomass, metrics that are used to characterize
the state of a fish population. The revised field index includes 3 new
macroscopic stages that represent final oocyte maturation in a batch of oocytes and were found to be reliable for staging spawning readiness in the field. The index was found to be suitable for studies of diel spawning periodicity and conforms to recent standardization guidelines.
... In other gadids, spawning activity and acoustic signalling seem to be tightly linked and primarily functions to attract females to spawning aggregations and provide a basis for mate selection (Burchard, Juanes, & Rountree, 2014;Hawkins & Rasmussen, 1978;Nordeide & Folstad, 2000;Nordeide & Kjellsby, 1999;Rowe, Hutchings, Skjaeraasen, & Bezanson, 2008). However, the specific function of acoustic signalling in burbot reproductive behaviour is not clear. ...
... The presence of a diel pattern in acoustic signalling with the majority of activity occurring at night is consistent with what has previously reported for burbot (Martin & Cott, 2016) and other gadoids, particularly Atlantic cod (Brawn, 1961;Hutchings, Bishop, & McGregor-Shaw, 1999;Nordeide & Kjellsby, 1999;Rowe & Hutchings, 2006) and haddock (Burchard et al., 2014), as well as other groups of fishes, such as the sciaenids (Holt, Holt, & Arnold, 1985;Lowerre-Barbieri et al., 2008;Walters et al., 2009). The results of the present study do not entirely resolve the role of acoustic signalling in burbot reproduction; however, when looked at in conjunction with the results of Cott et al. (2014), the calls recorded in Moyie Lake support the notion that acoustic signalling is part of the mating system for this species. ...
• Burbot (Lota lota: Gadidae) is a difficult species to manage effectively due to its preference for deep‐water habitats and under‐ice spawning behaviour, resulting in a poor understanding of its reproductive activity. However, the use of acoustic signalling by burbot as part of their mating system has recently been described and this behaviour may provide a means of investigating questions regarding the spatial and temporal distribution of spawning aggregations using passive acoustic monitoring.
• We used audio and video recording to confirm that burbot vocalise and that these vocalisations can be detected under field conditions as well as to characterise the relationship between burbot acoustic signalling and spawning behaviour. We also evaluated the feasibility of locating and monitoring burbot spawning aggregations in real time using passive acoustics.
• Burbot vocalisations were difficult to identify with only about 6% of the recordings containing calls being successfully identified as such in the field. Burbot vocalised more often between sundown and sunrise than during daylight hours. Calls recorded at night tended to be lower frequency, longer duration, and have lower bandwidth than those made during the day.
• Burbot vocalisations could not be recorded in conjunction with video recordings of spawning activity, indicating that burbot may not call during active spawning, but may use acoustic communication to signal the onset of reproductive readiness and to form pre‐spawning aggregations.
• While burbot calls were readily identifiable, observers had a difficult time identifying burbot calls in real time under field conditions. Passive acoustic monitoring demonstrates considerable potential as a management tool to locate burbot spawning grounds and identify periods of activity, but may not be an appropriate technique for monitoring spawning activity in real time.
... In other gadoids, such as Atlantic Cod and Haddock, spawning activity and acoustic signaling seem to be tightly linked and thought to primarily function to attract females to spawning aggregations and provide a basis for mate selection (Hawkins and Rasmussen 1978;Nordeide and Kjellsby 1999;Nordeide and Folstad 2000;Burchard et al. 2014). However, the specific function of acoustic signaling in Burbot reproductive behavior is not clear. ...
... The presence of a diel pattern in acoustic signaling with the majority of activity occurring at night is consistent with what has previously reported for Burbot (Martin and Cott 2015). This nocturnal behavior is consistent with behavioral patterns observed in other gadoids, particularly Atlantic Cod (Brawn 1961;Hutchings et al. 1999;Nordeide and Kjellsby 1999;Rowe and Hutchings 2006) and Haddock (Burchard et al. 2014), as well as other taxa, most notably sciaenids (Holt et al. 1985;Lowerre-Barbieri et al. 2008;Walters et al. 2009). The results of the present study do not resolve the question of what is the role of acoustic signaling in Burbot reproduction, but do suggest that acoustic signaling is not a consistent component of Burbot behavior in Moyie Lake when actively engaged in spawning. ...
Grabowski T. B. 2016. Assessing the feasibility of using acoustic monitoring for Burbot conservation, management, and production. Report provided by the Cooperative Fish and Wildlife Research Unit Program under agreement with the U.S. Fish and Wildlife Service. U.S. Department of Interior, Fish and Wildlife Service, Cooperator Science Series FWS/CSS-118-2016, National Conservation Training Center.
... Although a majority of cod and haddock were caught at depths between 50-70 m, nearly 4× as many haddock were captured in less than 40 m depth than cod. Many of these haddock were captured during spring fishing trips on Stellwagen Bank, a peak spawning location for haddock from February to April that can attain depths as shallow as 20 m (Burchard et al., 2014). Higher CPUE values for haddock may therefore be a result of higher abundances of fish that lead to higher catchability. ...
Terminal tackle regulations can be a valuable tool for fisheries management, especially in multispecies fisheries where bycatch and discards are common issues. In the
Gulf of Maine, recreational anglers frequently discard critically depleted Atlantic cod
Gadus morhua L. as bycatch when targeting the abundant haddock Melanogrammus
aeglefinus (L.) stock. The present study investigated species catch composition, catch
rates and animal welfare across various terminal tackle setups, and aspects of capture
and handling with the goal of reducing bycatch and discard mortality. Overall, 2558
cod and 4266 haddock were captured with six terminal tackle setups in the western
Gulf of Maine from April to October 2018. Along with angler experience and capture
depth, lure type primarily influenced species catch composition and catch-per-uniteffort; hook types additionally influenced hook-removal times and physical injuries
to fish. Results indicate that using baited hooks can both promote haddock catch and
reduce cod bycatch, with specific hook types promoting increased survival.
... The existence of the nocturnal rumbling suggests that haddock are more active in their displays at night, and that spawning may be a predominantly nocturnal activity. This hypothesis is supported in recent work by Burchard et al. (2014) which showed that in the Gulf of Maine the proportion of haddock at the final stage of spawning was highest during night, between 2100 and 0100 h. However, since individual sounds were often detected from haddock during the day in Balsfjord, it is concluded that some of the males were continuing their display activities, even under daytime conditions. ...
... The existence of the nocturnal rumbling suggests that haddock are more active in their displays at night, and that spawning may be a predominantly nocturnal activity. This hypothesis is supported in recent work by Burchard et al. (2014) which showed that in the Gulf of Maine the proportion of haddock at the final stage of spawning was highest during night, between 2100 and 0100 h. However, since individual sounds were often detected from haddock during the day in Balsfjord, it is concluded that some of the males were continuing their display activities, even under daytime conditions. ...
Stellwagen Bank National Marine Sanctuary is located in Massachusetts Bay off the densely populated northeast coast of the United States; subsequently, the marine inhabitants of the area are exposed to elevated levels of anthropogenic underwater sound, particularly due to commercial shipping. The current study investigated the alteration of estimated effective communication spaces at three spawning locations for populations of the commercially and ecologically important fishes, Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). Both the ambient sound pressure levels and the estimated effective vocalization radii, estimated through spherical spreading models, fluctuated dramatically during the three-month recording periods. Increases in sound pressure level appeared to be largely driven by large vessel activity, and accordingly exhibited a significant positive correlation with the number of Automatic Identification System tracked vessels at the two of the three sites. The near constant high levels of low frequency sound and consequential reduction in the communication space observed at these recording sites during times of high vocalization activity raises significant concerns that communication between conspecifics may be compromised during critical biological periods. This study takes the first steps in evaluating these animals’ communication spaces and alteration of these spaces due to anthropogenic underwater sound.
1. Introduction 2. Estimation 3. Hypothesis testing 4. Graphical exploration of data 5. Correlation and regression 6. Multiple regression and correlation 7. Design and power analysis 8. Comparing groups or treatments - analysis of variance 9. Multifactor analysis of variance 10. Randomized blocks and simple repeated measures: unreplicated two-factor designs 11. Split plot and repeated measures designs: partly nested anovas 12. Analysis of covariance 13. Generalized linear models and logistic regression 14. Analyzing frequencies 15. Introduction to multivariate analyses 16. Multivariate analysis of variance and discriminant analysis 17. Principal components and correspondence analysis 18. Multidimensional scaling and cluster analysis 19. Presentation of results.
Data from the Scottish participation in the International Young Fish Survey for the period 1976 to 1993 were analysed to examine the effect of light level and depth on catch rates. The species selected for this study were common dab, herring, haddock and whiting. Differences between day and night were observed for the juvenile common dab and herring and for the adult common dab and haddock. Differences between shallow and deep water were observed for the juveniles of all the species and for the adults of common dab, haddock and whiting. The mean lengths and the composition of the common dab and whiting catches were affected by both light and depth, indicating behaviour differences between the juveniles and adults of these species. While light seems to have no effect on the mean length and the catch composition of herring, differences were observed between shallow and deep waters. In the case of haddock, neither the light level nor the depth had any noticeable effect on the mean length and catch composition of the catches. We conclude that the diel behaviour and he geographic distribution are important factors in determining the quantity and composition of trawl catches, but their effects are species dependent. When trawl surveys are not exact replicates in terms of fishing times and areas, the estimation of catch indices should allow for the possible bias introduced by these factors. There is a need for models of the capture process that take account of such effects.