Harbor porpoises in the Flensburg Fjord

Harbor porpoises are the only native cetaceans in Germany. They are very shy animals, and thus, less known when compared to bottlenose dolphins or other dolphin species. However, it is possible to meet harbor porpoises in their natural habitat in the Baltic Sea with a little bit of luck. I joined a porpoise watching tour in the Flensburg Fjord in North Germany to search for harbor porpoises. In this blog entry I tell you more about this porpoise watching tour, but also about the threats harbor porpoises are exposed to.

The beginning of a journey...

The MS Flora II is ready for departure. Me and 11 more people have already taken a seat in the small boat. The tour will start in a few minutes.

To the harbor porpoises.

The sky is cloudy and it's windy.

When it gets cold, we can have a blanket to cover our legs and feet.

MS Flora II
MS Flora II in the harbor of Flensburg

It is late afternoon and many people walk along the harbor of the Flensburg Fjord.

I do not care much about the busy harbor as my thoughts are elsewhere.

Will we see harbor porpoises today?

I ask myself this question again and again.

Maybe we will.

Maybe not.

I very hope we will.

I ignore all the voices around me for a moment and think about my journeys in the past.

It would be the first time for me today to see harbor porpoises. I have never seen them before. I have seen dolphins and whales. In Australia, South Africa, Brazil, Slovenia and Spain. But harbor porpoises? And this in Germany? No. Never.

Tip: There is a trail in the Flensburg Fjord from Flensburg to Krusau and Kappeln. The name of this trail is Fördesteig and reaches a length of about 90 kilometers. Along the trail you will find more information about the harbor porpoises in the Flensburg Fjord, as apparently sometimes it is possible to observe these cetaceans on a walk along the fjord.

Harbor porpoises

Porpoises (Phocoenidae) are toothed whales like dolphins (Delfinidae) and sperm whales (Physeteridae).  There are seven different species of porpoises worldwide. The harbor porpoise (Phocoena phocoena) is one species.

The harbor porpoise lives in the Baltic and North Sea, but also further north in the North Atlantic. They also occur in western North Africa, in eastern and western North America, in the Black Sea and in the North Pacific in Asia.

There are two different harbor porpoise populations in the Baltic Sea. There is one population around Denmark and Schleswig-Holstein (state in the north of Germany) and another one more central and east in the Baltic Sea. There is no reliable statistic about the numbers of harbor porpoises in the Baltic Sea. However, it is estimated that the western population probably involves a population of a few thousands of animals and the eastern population, in contrast, only a few hundreds (probably 300).

Thus, harbor porpoises are widely distributed, but probably not all populations have a sufficient size to survive in the long term.

As a comparison, the vaquita - another porpoise species - lives only in the waters of Baja California and does not occur in any other place on earth. Apparently, there are only 10 (!) vaquitas left in the wild (July 2019).

When compared to the vaquita, harbor porpoises are doing fine. However, this does not mean at all that we do not have to worry about them.

If we consider that the eastern population comprises probably only about 300 animals, we have to be concerned. Especially due to the fact, that this population does not reproduce with other populations. There is no genetic exchange between these harbor porpoises and other porpoises of the Baltic Sea. Thus, it is very important to protect these animals in the eastern part of the Baltic Sea.

As a comparison.

About 15 years ago, more than 200 vaquitas still lived in the waters of Baja California. Now only 10 individuals are left.

As you can see, if we do not protect the harbor porpoises in the eastern Baltic Sea, these cetaceans might be like the vaquita at the brink of extinction in a few years, too.

It is important to mention hear that harbor porpoises prefer coastal waters. Thus, their habitat overlaps with the habitat of humans. This is not very beneficial for these animals, as the closer they are to humans the more they are exposed to human-induced threats.

I will write more about these threats in the next paragraphs.

Flensburger Förde
Habitat of harbor porpoises in the Flensburg Fjord

The harbor porpoise can be distinguished from most dolphins like bottlenose dolphins by their cone-like shaped head and their short snout.

Furthermore, harbor porpoises are small cetaceans and usually reach a length of less than 2 meters.

The dorsal fin is triangular and the color of the animal ranges from dark grey on the back to light grey on the ventral side.

Porpoise on an exhibition

Harbor porpoises are rather shy animals, and thus, difficult to observe. They live in small groups of less than 10 animals. On average, mostly between 2 and 8 porpoises. They are not that acrobatic like bottlenose dolphins and they do not show so much of themselves at the water surface.

If you want to observe harbor porpoises or in general wild animals, respectively, you really need to bring along one thing: patience.

The best thing you can do on such a tour is to join without any expectations as you need not only patience, but also good luck.

Tip: Do you want to know more about harbor porpoises? You will find more information about these cetaceans on the website of Animal Diversity. On this website you will find much information about harbor porpoises, but also about many other animals.

A harbor tour in the Flensburg Fjord

Finally it's 6 p.m.

The MS Flora II leaves the harbor and the boater navigates the boat towards the Danish coast of the Flensburg Fjord as they have spotted many harbor porpoises in these waters in the last few days.

Hopefully we are lucky today, I think.

I try to keep my expectations as small as possible.

But anyway, I prepare my camera.

Just in case.

The sky opens and some sunrays color the surrounding landscapes slightly in a warm light.

The harbor tour in the Flensburg Fjord is organized by an employee of the NABU (a German NGO focused on the conservation of nature and biodiversity).

Why do they offer porpoise watching tours in the Flensburg Fjord?

When and where is it possible to observe harbor porpoises?

And what are the threats these cetaceans are exposed to?

These questions are the central topics of the harbor tour.

As harbor porpoises are very shy marine mammals, and furthermore, as only few people know these animals, these cetaceans urgently need more attention.

If they do not get more attention, maybe one day they will end up like the vaquita in Baja California.

Harbor porpoises do not  have a very strong lobby, and thus, political decisions often are not on their side.

Thus, why not establish a stronger lobby for these cetaceans through harbor tours in the Flensburg Fjord?

As female harbor porpoises spent the summer months close to the coast with their offspring, many of them can be observed in July or August close to the coast in the Baltic Sea. Including in the Flensburg Fjord.

Flensburger Förde
Landscape in the Flensburg Fjord

The NABU started with these harbor tours only a few years ago. Important to mention here is that volunteers organize these tours. Profit has not a priority, but outreach as the harbor porpoise in the Baltic Sea needs more people standing up for its conservation.

However, this is not an easy task as harbor porpoises are so shy and they do not appear for a long time at the water surface. Therefore, it is more difficult to fill people with enthusiasm for these cetaceans.

In July they have seen harbor porpoises on every tour in the Flensburg Fjord in the 2019 season. In one occasion only for a short moment and not everyone on the boat spotted these fast marine mammals, however, the porpoises were around.

Last year they have seen harbor porpoises on almost every tour. In other years they saw them on only every second tour. However, the longer they offer these tours, the more they know where to find them.

Flensburger Förde
Landscape in the Flensburg Fjord

By the way, the people from the NABU have observed especially many harbor porpoises when Ric O’Barry visited the Flensburg Fjord. Ric O'Barry is an animal activist who was part of the documentary "The Cove" to raise awareness for the dolphins that die in the cove of Taiji in Japan.

Maybe we are lucky, too?

Yes, we are.

Two harbor porpoises emerge at the water surface just in front of me.

Just for a few seconds - too fast to photograph them - but they have emerged.

What a wonderful encounter!

We saw two triangular dorsal fins. Maybe a mother and her calve?

Harbor porpoises below the water surface

The boat stops for a few minutes.

Maybe they will appear again?

Unfortunately no.

They have already left and we leave, too.

Apparently, there is another region in the Flensburg Fjord where many harbor porpoises have been seen in the past few days.

So we leave into this direction.

Do the harbor porpoises emerge at the water surface again?

Unfortunately no.

However, instead we learn more about the Flensburg Fjord, the harbor porpoises, and most importantly, all the threats these marine mammals in the Baltic Sea are exposed to.

Tip: If you want to take photographs of marine mammals like porpoises you need especially much patience and good luck. Most of the time you have to guess where the animals might emerge at the water surface again (if they emerge at all). If they emerge at the water surface, it might be already too late for a photograph. My tip is: be patient with yourself. I took many photographs of whales and dolphins in the past. However, I had the chance to take these photographs on several (and not only one) whale watching trips.

Threats to harbor porpoises

My principal aim of this blog entry is to inform you about the threats harbor porpoises are exposed to in the Baltic Sea. But where should I start? To be honest, there are quite many threats and it is not easy to narrow down these threats to one topic. Therefore, I will give you here an overview and where you can find more information.

Underwater blastings

One photograph I remember quite well from the harbor tour was the one of a small, dead and blood-smeared harbor porpoise. If you want to see this photograph, go onto the website of the NABU. This photograph made me very sad and now sticks in my mind.

But why was this baby harbor porpoise washed ashore on the coast in the Baltic Sea?

As this animal was found only three days after a major underwater blasting, it is very probable that this underwater blasting was the reason for the death of this baby animal.

As I do not live at the coast in the Baltic Sea, it was the first time that I heard about all this.

Underwater blastings.

All porpoises (dolphins, too) use echolocation in order to locate and identify their prey. That means, they emit sound waves which reflect back to the animals. In other words, porpoises see with their ears. Therefore, they need intact ears for navigation and foraging.

However, these loud underwater blastings cause such a big noise that the organs of a harbor porpoise is damaged.

I do not understand why politicians allow such underwater blastings in an area where cetaceans and many other animals live. These kind of decisions just shows me how "important" the protection of nature in Germany is.

Nevertheless, in Schönhagen in Schleswig-Holstein there are apparently underwater blastings at the coast on a regular basis.

And apparently, the underwater blastings are so strong that even the bread in the local bakery falls from the shelves to the ground. I have never experienced one, but our tour guide on the porpoise watching tour told us about how the earth was shaking during such an underwater blasting.

It is easy to imagine that these underwater blastings are harmful for harbor porpoises. One thing that makes me really upset about all this, how should the animals know about all this, and thus, how should they avoid such underwater blastings?

I have to repeat. I do not understand why they don't care about marine wildlife in the Baltic Sea.

And why do they undertake such underwater blastings? Well, for example during military exercises or in order to test the stability of naval vessels.

Just to name two examples.

But still I do not understand why they have to do that in an area where harbor porpoises live. Especially in summer when females stay close to the coast with their calves.

That is very difficult to understand.

However, this baby harbor porpoise is just one of several other porpoise found dead after such an underwater blasting.

Questions: Have you experienced once such an underwater blasting close to your home? If yes, please share your experiences in the comments. Did it feel like an earthquake? And have you encountered dead animals along the coast after such an underwater blasting?

Water pollution

Another information which was very concerning for me was the fact that the habitat of the harbor porpoise is very contaminated (very contaminated!). For example, did you know that it is prohibited to bury a dead marine mammal of the Baltic Sea in the ground? As they are so contaminated, they have to be disposed as hazardous waste.


How can we do such a thing to these marine mammals?

This makes me sad and angry at the same time.

At that precise moment I had to think about the humpback dolphins in South Africa. They also live close to the coast, and thus, are exposed to several human-induced threats like water contamination. In humpback dolphins, for example, high water contamination leads to miscarriages. As this population is endangered, these are very sad facts for this dolphin species.

humpback dolphin
Humpback dolphin along the coast in South Africa

There are also studies in harbor porpoises, and apparently, they have to suffer from a high water contamination, too. A high water contamination can affect the immune system of an animal and lead to miscarriages in this cetacean, too.

Most contaminants reach the Baltic Sea through rivers, but also through the air (see cruisers).

Questions: Do you live close to the coast? If yes, do you see many marine mammals on a regular basis? Which ones? And do you know more about their health status?

Plastic in the sea

One of the biggest challenge at the moment is probably our unthoughtful use of plastic. Plastic is a problem. In my opinion a very big problem. At the moment there is no month without any news about a whale or turtle washed ashore with a stomach full of plastic.

Of course, harbor porpoises also live in this sea of plastic, and consequently, plastic was found in the stomach of these cetaceans in the past, too.

The Ocean Conservancy calls for the International Coastal Cleanup every year in September. That means, people can organize themselves in groups, collect rubbish along coasts and beaches to document the items they found on that Coastal Cleanup day. I participated in the International Coastal Cleanup day for the first time during my stay in South Africa. If you are in Germany, you can also check the website of "Gewässerretter". On this website you can find groups that organize litter clean-up events in Germany.

It is great to see that there are people concerned about plastic and actively doing something against it. However, the best thing you can do is to avoid plastic at all. For example, you can buy food without single-use plastic (which is not always very easy, I have to admit). But not impossible? I try to avoid as best as possible single-us plastic in my daily life.

Only small actions, but in my opinion so necessary.

Just by refusing plastic bags, you have done a lot.

Questions: Have you ever participated in a litter clean-up event? Or are you reducing your plastic consumption at the moment? Do you have any tips?

Fishing with gillnets

Another threat that is responsible for many deaths in harbor porpoises is fishing with gillnets. Many harbor porpoises die because of this fishing method. Every year about 150 to 200 harbor porpoises are washed ashore along the German coast of the Baltic Sea. About half of them have died because of gillnets, because these small cetaceans entangle in these nets and drown.

According to our guide of the harbor tour, most fishermen of the Flensburg Fjord are interested in the protection of these marine mammals. However, outside of Flensburg it is more difficult to find an understanding fishermen.

There are acoustic warning devices like PAL (Porpoise Alert), but these precautionary measures do not work in every case.

Although they even reduce the size of gillnets when females enter the Flensburg Fjord with their calves in summer, fishing with gillnets is still one of the most prevalent cause of death in harbor porpoises.

Questions: Do you eat fish or other seafood? What do you think about overfishing? Do you think it is still healthy to eat fish given the fact that the Baltic Sea is highly contaminated?

More threats for harbor porpoises

Underwater blastings in the Baltic Sea.

Water contamination.


And fishing with gillnets.

Just to name a few threats harbor porpoises and marine wildlife in general is exposed to in the Baltic sea. I haven't mentioned yet noise by ships, especially by jet-skis or other fast boats. But also construction works (see wind power stations). To name some more threats.

Not to forget eutrophications through agriculture. Too many nutrients like nitrogen or phosphor in the Baltic Sea result in algae that multiplies at an explosive rate. Eventually, algae descends to the seafloor where it is degraded by using oxygen. The result is an oxygen-poor habitat with fewer available food resources.

Harbor porpoises in the Flensburg Fjord prefer mussel banks where they can hunt for fish. However, mussel banks are not in their best health status, neither. Mussels of mussel banks store especially many heavy metals, but also micro plastic. Thus, the regenerating capacity of mussels and mussel banks is reduced.

Questions: Do you know more threats for harbor porpoises and other marine wildlife? Do you think we can do anything against these threats? And what?

What will happen in the future?

What will happen to the harbor porpoises in the Baltic Sea? Do they have a survival chance?

Or will they end like the vaquita in Baja California?

That is difficult to predict, but our way of life is very concerning.

The future of these cetaceans depends mostly on all our decisions.

If we consider that harbor porpoises theoretically are able to live 20 years in the wild, but their life expectancy has decreased to 4 years on average, there is a reason to be concerned. A harbor porpoise reaches sexual maturity between 3 and 5 years and they calve only once a year at the maximum. How should they be able to survive given these facts?

I think it is very important to raise awareness for the situation of the harbor porpoises. Many people do not know that they live in the Baltic Sea or that they even exist.

In one thing I'm optimistic. According to our guide of the harbor tour there are many people interested in joining a porpoise watching tour. For your information, I had to wait one year to be able to participate in one of these tours. The tours are not expensive as they also want to offer tours for families. As mentioned above, profit is not their priority, but outreach. People should hear about the harbor porpoises in the Baltic Sea and tell more people about them.

And that is what I'm doing now with this blog entry. And please, let more people know about these wonderful animals in the Baltic Sea.

Resoures and more about harbor porpoises

Whales, Dolphins, and Seals – A Field Guide to the Marine Mammals of the World von Hadoram Shirihai und Brett Jarrett (Book)

Harbor Porpoise (Phocoena phocoena) from Arne Bjørge and Krystal A. Tolley (Book chapter: Encyclopedia of Marine Mammals)

"Reproductive Failure in UK Harbour Porpoises Phocoena phocoena: Legacy of Pollutant Exposure?" from Sinéad Murphy und Kollegen

You can find more information about the vaquita on the Facebook page of VIVA Vaquita

If you want to know more about how you can participate on a porpoise watching tour in the Flensburg Fjord, check the website of the NABU

"Schweinswale in Wilhelmshaven" (Englisch: "Harbor porpoises in Wilhelmshaven") on Torsten Berg's German blog (tberg.de)

Have you ever seen a harbor porpoise in the wild? Or have you searched for them in vain? Let me and the readers know in the comments. And please tell other people more about the harbor porpoises in the Baltic Sea.


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