Cutting-Edge Oceanographic Research Technology & Custom Instrumentation Solutions

The Pacific Islands Fisheries Science Center deploys the Modular Optical Underwater Survey System (MOUSS) to estimate the species-specific, size-structured abundance of commercially-important fish species in Hawaii and the Pacific Islands. The MOUSS is an autonomous stereo-video camera system designed for the in situ visual sampling of fish assemblages. This system is rated to 500 m and its low-light, stereo-video cameras enable identification, counting, and sizing of individuals at a range of 0.5–10 m. The modular nature of MOUSS allows for the efficient and cost-effective use of various imaging sensors, power systems, and deployment platforms. The MOUSS is in use for surveys in Hawaii, the Gulf of Mexico, and Southern California. In Hawaiian waters, the system can effectively identify individuals to a depth of 250 m using only ambient light. In this paper, we describe the MOUSS’s application in fisheries research, including the design, calibration, analysis techniques, and deployment mechanism.

Remotely Operated Vehicles (ROVs) are widely used in research, but testing new algorithms is challenging due to the limitations of simulations and the high cost and risk of real-world deployment. To bridge this gap, researchers developed an underwater test platform that simulates ROV operations in realistic conditions.

Investigating sub-ice aquatic environments, particularly in Antarctica, presents unique challenges that require specialized technology. While ice can provide a stable platform for deploying remotely operated vehicles (ROVs), traditional cuboid, tethered designs demand large-diameter holes—an impractical requirement given the logistical difficulty of ice drilling. Ship-deployed underwater vehicles offer some access beneath ice shelf fronts, but their limited range makes it difficult to reach grounding zones located hundreds of kilometers inland. As a result, scientific exploration in these environments has been limited. Borehole vehicles have shown promise in the past, and this work introduces a significantly enhanced version, offering greater depth capability and advanced capabilities.

This study examined Pacific salmon behavior inside pelagic trawls to improve bycatch reduction. Video observations showed most salmon (71%) moved aft toward the cod end, while only 24% moved forward, with forward movement increasing when trawl speed and water flow decreased during haulback. Forward movement was negatively correlated with vessel speed and Walleye Pollock abundance. Only 6.5% of salmon in the cod end moved forward after fishing ended, indicating low escapement late in the tow. Findings suggest bycatch reduction devices should prioritize encouraging salmon escape earlier in the trawl.

This study presents in situ measurements of mean and turbulent bottom stresses over cohesive sediments in shallow, wave- and current-driven flow in South San Francisco Bay. Using high-resolution velocity data, researchers found that biological roughness created canopy-like shear layers, affecting flow structure. Wave-current interactions increased drag, with wave-induced momentum flux dominating near the bed. Traditional methods of estimating bottom stress were consistent above the wave boundary layer but underestimated total stress at the bed.

The skate Leucoraja erinacea has an elaborately shaped pupil,
whose characteristics and functions have received little attention. The
goal of our study was to investigate the pupil response in relation to
natural ambient light intensities. First, we took a recently developed
sensory–ecological approach, which gave us a tool for creating a
controlled light environment for behavioural work: during a field
survey, we collected a series of calibrated natural habitat images from
the perspective of the skates’ eyes. From these images, we derived a
vertical illumination profile using custom-written software for
quantification of the environmental light field (ELF). After collecting
and analysing these natural light field data, we created an illumination
set-up in the laboratory, which closely simulated the natural vertical
light gradient that skates experience in the wild and tested the light
responsiveness – in particular the extent of dilation – of the skate pupil
to controlled changes in this simulated light field. Additionally, we
measured pupillary dilation and constriction speeds. Our results
confirm that the skate pupil changes from nearly circular under low
light to a series of small triangular apertures under bright light. A linear
regression analysis showed a trend towards smaller skates having a
smaller dynamic range of pupil area (dilation versus constriction ratio
around 4-fold), and larger skates showing larger ranges (around 10-
to 20-fold). Dilation took longer than constriction (between 30 and
45 min for dilation; less than 20 min for constriction), and there was
considerable individual variation in dilation/constriction time. We
discuss our findings in terms of the visual ecology of L. erinacea and
consider the importance of accurately simulating natural light fields in
the laboratory.