Research Highlights
Seeking ghost shark secrets
The spotted ratfish presents a unique opportunity for studying a benthic shark. At Friday Harbor and in other parts of the Washington coast, this typically deep-sea species ventures into shallower waters to lay its eggs. I am locating these nursery sites to establish a more comprehensive record of its population and natural history. My curiosity extends to examining its embryonic development, unravelling the process by which ratfish develop their distinctive traits and predicting potential environmental influences. Our typical research days involve ventures onto the water, either aboard marine research vessels to collect population data and egg cases or utilising remotely operated vehicles to film and explore the seabed. Back in the lab, I process tissue to extract genetic and cellular information about growth and development. The footage captured by the remotely operated vehicles helps us to compare the habitats of different nursery sites, enabling us to craft interactive virtual reality exhibits that enable viewers to engage with ratfish, even from land.
Some fish loose up to 20 teeth a day!
Tooth replacement rates of polyphyodont cartilaginous and bony fishes are hard to determine because of a lack of obvious patterning and maintaining specimens long enough to observe replacement. Pulse-chase is a fluorescent technique that differentially colours developing mineralized tissue. We present in situ tooth replacement rate and position data for the oral and pharyngeal detentions of Ophiodon elongatus (Pacific lingcod). We assessed over 10 000 teeth, in 20 fish, and found a daily replacement rate of about two teeth (3.6% of the dentition). The average tooth is in the dental battery for 27 days. The replacement was higher in the lower pharyngeal jaw (LPJ). We found no difference between replacement rates of feeding and non-feeding fish, suggesting feeding was not a driver of tooth replacement. Lingcod teeth have both a size and location fate; smaller teeth at one spot will not grow into larger teeth, even if a large tooth nearby is lost. We also found increased rates of replacement at the posterior of the LPJ relative to the anterior. We propose that lingcod teeth do not migrate in the jaw as they develop; their teeth are fated in size and location, erupting in their functional position.
Dimorphic fluorescence in Pacific Spiny Lumpsuckers.
Joining the ranks of vertebrates that glow is the Pacific Spiny Lumpsucker, Eumicrotremus orbis, a subtidal species widely distributed across the North Pacific Ocean. Aside from their charismatic appearance, the Pacific Spiny Lumpsucker is known for its ventral suction disc that is used to stick to substrates amid changing currents and tides. Here we show that red lumpsuckers, which are usually male and a deep red color under broad-spectrum light, fluoresce bright red under ultraviolet (UV) light and blue light (360–460 nm), while green color morphs (usually female) do not. In all color morphs, the suctorial disc glows green-yellow. The red glow of the males matches the red glow of encrusting algae in their nesting areas, while the suctorial disc may be a signaling system. The green and red fluorescence observed in red lumpsuckers is the rarest fluorescent pattern and is only seen in 17 families of marine fishes. Pacific Spiny Lumpsuckers are cryptically colored under broad-spectrum light; our observed fluorescence suggests a potential avenue of communication and camouflage in an environment where red light is absent or rare.
Check out our story in the New York Times!
Development of Lumpsucker Odontodes
Predation, combat, and the slings and arrows of an abrasive and high impact environment, represent just some of the biotic and abiotic stressors that fishes are armored against. The Pacific Spiny Lumpsucker (Eumicrotremus orbis) found in the subtidal of the Northern Pacific Ocean is a rotund fish covered with epidermal, cone-shaped, enamel odontodes. We use micro-CT and SEM to reveal the morphology and ontogeny of the armor, and to quantify the amount of mineralization relative to the endoskeleton.
Functional Homodonty and the conical tooth
If teeth all look the same we refer to them as homodont, and when they look different we refer to them as heterodont. However these measures of shape alone miss a great deal of variation within conical teeth. Looking at the selective pressures of load and stress we are creating statistical models to see how function enforces particular tooth shapes.
Ontogeny of specialized filtering plates in silver carp
Silver carp are invasive filter feeders able to eat particles of food as small as 5 microns. This research looks at the development and functional morphology of the filtering apparatus in silver carp. Looking at the morphology through classical anatomical techniques and micro-CT we hope to answers questions about how silver carp are able to out compete filter feeders across trophic levels.
Fluid dynamics of filter feeders
Filter feeding fishes capture particles of food using a variety of mechanisms. this work focuses on filter feeding Asian carp and how their filtering mechanism differs from those previously described.
Otocephalan epibranchial organs
Eating small particles of food is hard. Fishes have to retain and aggregate particles in an efficient way. Epibranchial organs have independently evolved at least six times and are food aggregating structure found in certain teleosts. Morphologically complex and diverse this work analyzes the functional morphology of epibranchial organs to see how and why they different in form and function.