Advancing fishery-independent stock assessments for the Norway lobster (Nephrops norvegicus) with new monitoring technologies

Abstract

The Norway lobster, Nephrops norvegicus, supports a key European fishery. Stock assessments for this species are mostly based on trawling and UnderWater TeleVision (UWTV) surveys. However, N. norvegicus are burrowing organisms and these survey methods are unable to sample or observe individuals in their burrows. To account for this, UWTV surveys generally assume that “1 burrow system = 1 animal”, due to the territorial behavior of N. norvegicus. Nevertheless, this assumption still requires in-situ validation. Here, we outline how to improve the accuracy of current stock assessments for N. norvegicus with novel ecological monitoring technologies, including: robotic fixed and mobile camera-platforms, telemetry, environmental DNA (eDNA), and Artificial Intelligence (AI). First, we outline the present status and threat for overexploitation in N. norvegicus stocks. Then, we discuss how the burrowing behavior of N. norvegicus biases current stock assessment methods. We propose that state-of-the-art stationary and mobile robotic platforms endowed with innovative sensors and complemented with AI tools could be used to count both animals and burrows systems in-situ, as well as to provide key insights into burrowing behavior. Next, we illustrate how multiparametric monitoring can be incorporated into assessments of physiology and burrowing behavior. Finally, we develop a flowchart for the appropriate treatment of multiparametric biological and environmental data required to improve current stock assessment methods.

Underwater legged robotics: review and perspectives

“…Furthermore, the station keeping capabilities of ULRs, which can yield to high precision geo-positioning, would allow direct vertical, high-frequency, and prolonged observation of burrow systems in benthic species of high commercial relevance to conclude on their presence and activity (e.g. Norway lobster can be captured by trawls only when outside the burrows [22]). The presence of robotic manipulators would allow water and sediment sampling around tunnel systems to determine relevant life traits phenomena such as multiple burrow occupancy.…”

“…Notwithstanding the advantages of crawlers over pelagic robots in the benthic environment, they still present intrinsic drawbacks in terms of mobility and impact on the seabed that limit the execution of relevant tasks. Crawlers cannot move on rocky terrains and need almost continuous ground [22,23]. At the same time, their tracks cause significant sediment resuspension, which affects the quality of video recording and impairs the visibility of the operator.…”

Towards a global Fishing Vessel Ocean Observing Network (FVON): state of the art and future directions

“…The inspiration for many of the pioneering programs instrumenting fishing gear was to collect the data necessary to enable the next generation of dynamic and ecosystem-based fisheries management strategies (Carpi et al, 2015;Russo et al, 2015). These advances link fisheries and fish resources distribution to ecosystem health and oceanographic conditions to increase the knowledge of environmental drivers of the spatio-temporal distribution of fish populations and thus enable better management decisions that increase the ecological and economic sustainability of fisheries (Aguzzi et al, 2022;Chiarini et al, 2022). Climate change is causing shifts in the distribution of marine species at approximately an order of magnitude faster than those on land (Poloczanska et al, 2013).…”

Occurrence and behavioral rhythms of the endangered Acadian redfish (Sebastes fasciatus) in the Sambro Bank (Scotian Shelf)

“…If the close association with the seabed during the daylight hours is necessary for digestion, then environmental changes occurring there also have the potential to disrupt the energy budgets and ultimately growth rates. Under this scenario, monitoring activities in relation to fishery independent assessment procedures will be highly relevant specially when dealing with threatened species (Aguzzi et al, 2022).…”