Environmentalists in Florida are calling on the governor, Ron DeSantis, to declare an emergency as a worsening “red tide” algae bloom off the state’s south-west coast threatens popular tourist beaches and is being blamed for the deaths of wildlife including fish and dolphins.

Several counties have issued health alerts in response to the outbreak, which scientists say began in the Gulf of Mexico last year when Hurricanes Helene and Milton tore up nutrient-rich waters that feed the algae.

The Florida fish and wildlife conservation commission (FWC) has been monitoring a sizable patch of red tide, a naturally occurring phenomenon caused by overproduction of the harmful algae Karenia brevis, along a stretch of the Gulf coast. Dead fish have washed up on several beaches, and the outbreak is suspected in the deaths of two dolphins found offshore in Collier county.

Red tides can cause skin irritation and respiratory distress in humans and animals, and have become increasingly common in recent years, partly due to a combination of changing environmental conditions, including soaring ocean temperatures, and pollution. In many instances they dissipate by January, but in other years can linger and worsen, such as the severe summer 2021 outbreak that left heaps of fish, turtles, dolphins and manatees rotting on the Florida shoreline.

The conservation groups say not enough is being done to tackle the cause of the problem, even though they applaud efforts such as DeSantis’s reactivation of a red tide taskforce in 2019, and his signing of a house bill last year extending funding for research.

“While providing funds for engineering solutions, the government has not done a very good job at controlling or fixing polluted waterways,” said Eric Milbrandt, marine lab director of the Sanibel-Captiva Conservation Foundation (SCCF).

The group has previously linked human activity, including toxic run-off from agricultural production, as an aggravating factor in the intensification of red tide events.

“We have a lot of them in the state of Florida, and it’s non-point source pollution, so it’s difficult to tackle. It’s great that the state has been investing in engineering technology, and it does have promise, but it likely would be limited to smaller blooms,” Milbrandt said.

“From a response perspective, it should be kind of an emergency management response like a hurricane. At this point it’s reliant on the department of health to post it, the Florida Wildlife Research Institute to collect the samples, and by the time it’s affecting a community there’s potentially millions of dollars in revenue and tourism economy [at risk].

“We just want something to happen here. A statewide approach, like an emergency management approach, would be useful.”

FWC researchers, in partnership with scientists from the Sarasota’s Mote Marine Laboratory, and Florida’s department of environmental protection (DEP), share responsibility for red tide mitigation, and point to improvements made under DeSantis’s watch.

“FWC has increased routine sampling, added new measurements, and are planning an event response survey with a collaborative team. We have improved communication tools, like creating a series of educational red tide animated videos,” a FWC spokesperson, Jonathan Veach, said in a statement.

“FWC works with partners to produce metrics of severity based on bloom extent and duration. Our agency is not the entity who would make an official declaration of emergency.”

Veach added: “Thus far, while recognizing the current intensification, this red tide bloom is still fairly typical in terms of timing, intensity and location.”

A DEP spokesperson said department personnel had been working closely with FWC and health department workers to engage stakeholders and local governments in south-west Florida since the first red tide formations appeared in October.

“Florida remains committed to an all-hands-on-deck approach and continues to monitor the bloom and while remaining ready to assist affected counties,” its communications director, Alexandra Kuchta, said.

“Dedicated funding is available to support local communities in their red tide response efforts, including assistance for this event if necessary, although none has been requested so far. For fiscal year 2024-25, $5m was allocated, with an additional $5m proposed for 2025-26.”

Kuchta added that DeSantis had also approved funding for innovative technologies that can be “deployed immediately to protect water quality and public health from future harmful algal blooms, including red tide response”.

A Mote representative told the Guardian that the south-west Florida bloom provided its researchers a first opportunity to “field test” several mitigation technologies on an active bloom in uncontrolled open water.

“We’ve made a lot of progress on understanding the lab rat version of this species. The wild type, so to speak, that’s out in the ocean can behave in ways you can’t replicate in the test tube,” SCCF’s Milbrandt said.

Meanwhile, a page on the federal Environmental Protection Agency website still online as of Tuesday blamed the climate emergency, especially warming ocean waters, for more toxic and frequent algal blooms such as the one menacing the Florida Gulf coast.

“With a changing climate, harmful algal blooms can occur more often, in more fresh or marine waterbodies, and can be more intense,” it states.

So far, at least, the page appears to have escaped a Trump administration purge of mentions of the climate crisis on government websites. Florida already has a law scrubbing mentions of “climate change” from state legislation, and the University of Pennsylvania climate scientist Michael Mann said DeSantis and Florida “were indeed the test bed” for similar censorship at the federal level.

“Nothing would surprise me at this point, including efforts by the administration and the polluters who are running it to ban all references to climate change by administration agencies,” he said.

DeSantis’s office did not respond to a request for comment from the Guardian.